A few days ago I sent this feedback to Larian, and now I’m posting it here so everyone can discuss each point, although I’ve made some additions, as marked under [EDIT] below. It is pretty extensive and sometimes repetitive since I went over every single spell I could remember. Here it goes:

This is going to be a big one (that’s what she said), but I’m sending a complete feedback on each spell/cantrip on the game, after my 150+ hours of playing, so just a little heads up. Remember that you asked for it.

First of all, the biggest problem me and my friends find with spells are the "control spells", since saving throws are being rolled at the start of creatures' turns. This makes control spells really weak compared to damage spells and really not worth using at the moment. For example, hold person is probably the best control spell on dnd 5e, and in BG3 it’s just a waste of your spell slot and turn, since the target will roll its saving throw when you cast the spell, and again at the START of its turn, so there is a huge chance you will waste your action and spell slot and the creature won't lose even 1 turn.

Besides this problem, there is also the concentration problem. Losing concentration in BG3 is way easier than in dnd 5e, since surface damage bypasses the bounded accuracy created in dnd 5e (it was created to balance combat, and surface damage currently breaks it, as I'm sure Larian has already taken notice by the huge amount of negative feedback on surface damage). Still regarding concentration, the "prone" condition and pretty much any shove/push effect you take (which are too common currently) also break your concentration without even a saving throw being rolled, making it nearly impossible to hold concentration on a spell during combat, due to all the unavoidable damage and prone/pushing effects.

Therefore, the control spells at the moment are just a waste of a spell slot and action, since the creature will probably not lose one single turn, making the "ray of frost" cantrip better than all control spells, which also goes back to the surface problem.

Another big problem with spells is the so called “verticality” that only seems to work from higher grounds to lower grounds. There is really no reason to why I am able to cast a projectile spell on a creature on the top of a roof but cannot cast an area spell on the exact same spot because the game says it is “TOO HIGH”. I really hope this is a bug and not a design option, because it just makes most spells (usually the control ones) even more useless. If is not too high for my firebolt it should not be too high for my fog cloud, since all I need is a line of sight.

On a smaller note, please remove the ability for wizards to learn spells from other classes, it is really breaking immersion right now.

Now with a list of each spell and their individual feedback (from me and my 2 friends that play with me currently):

1) Cantrips
Acid Splash – This spell is fine and is a great way to show how implementing surfaces doesn’t require to ignore the bounded accuracy, since its surface doesn’t cause direct damage. [EDIT] I feel the -2AC buff should only be applied to creatures that were originally hit by the spell though, not everyone that stands on the surface.
Blade Ward – The tooltip needs work, since it says the buff will be applied for 2 turns, when it’s actually just one. This is also a reflection on the saving throws being rolled at the start of turns, since the “on turn” effects are happening at the start of turns rather than at the end.
Chill Touch – Works fine, but I think really think the part of “a spectral hand appears and touches the target” could be implemented into the animation, as it would look pretty cool.
Dancing Lights – Works perfectly, no changes required.
Eldritch Blast – I’m not sure charisma or proficiency is properly added to the “to hit chance %”, since this cantrip seems to have a lower chance to hit than ranged weapons under same conditions. Also, repelling blast seems to be ignoring falling damage when pushing creatures from high grounds. On a personal note, it would be nice to add the “grasp of hadar” invocation, as a counterpart of the repelling blast.
Firebolt – As mentioned above and by most feedback on surface damage, this is the most problematic cantrip at the moment, since it bypasses the bounded accuracy and is a guaranteed damage (making it sometimes better than sorching ray – a 2nd level spell). The damage should be increased to at least 1d8 and the fire surface should only be created when it targets the floor, not a creature. [EDIT] Another issue with the surface created by this cantrip is that other characters can “dip” their weapons in the fire, making it a huge buff to the team and further breaking the balance of what a cantrip should do. As it is now, firebolt is looking like a 2nd level spell with all the benefits it brings. Maybe the surface should last only one round to make it harder to “dip” weapons or add only a fixed +1 fire damage to weapons so that it is not that powerful.
Friends – As most out-of-combat spells, this cantrip should be castable during conversations. Many conversations trigger by just approaching a character, making it impossible to cast this cantrip before the conversation starts.
Guidance – This cantrip seems to not properly add the bonus in dice rolls during conversations. I am not sure it is adding it to automatic skill checks.
Light – Although this cantrip creates a nice light effect for the player, it is ignoring the effects of light to creatures without darkvision during combat. For example, a human with a Light cantrip cast on its weapon will still have the “target obscured by shadows” on its melee weapon attacks during combat.
Mage Hand – At the moment, mage hand has too many utilities in combat and nearly none out of combat, which is kind of the opposite of how it works in dnd 5e. It should not be able to throw enemies and its carrying capacity should be limited by weight, especially since every object and creature has a specific weight already. Also, anyone should be able to pass through the mage hand. The githyanki version of it is also creating an invisible mage hand, like the one created by arcane tricksters, and I’m not sure this is intended. Lastly, mage hand should be able to pickpocket creatures (especially the one created by arcane tricksters, which at the moment do not have any benefits from a normal mage hand aside from being invisible).
Minor Illusion – This cantrip is fine, although the animation could be improved, since the spectral scarecrow seems a little too humorous (not in tone with the sinister aspect of the game). Maybe it could prompt options (like the “hex” and “conjure familiar” spells) and we could choose to create a sound or a few images.
Poison Spray – No works needed. The cantrip works perfectly.
Ray of Frost – Aside from being the most powerful control spell in the game so far, the rest of the cantrip is pretty good. The ice surface REALLY needs rework, because not only it makes characters prone (which is one of the best conditions at the moment due to breaking concentration without a saving throw, removing the ability to make dexterity saving throws and finishing the creature’s turn) when cast, but there is also a chance to make it prone again during its turn, which instantly finishes the creature’s turn, and it probably shouldn’t. So along with the ice surface, the “prone” condition really needs to be balanced.
Resistance – I’m not sure the bonus is being added to saving throws rolled at conversations. Aside from that, the cantrip is fine.
Sacred Flame – Works perfectly and I love the animation.
Shocking Grasp – This is a good example of how firebolt and surfaces can work without breaking the game’s balance. When shocking grasp is cast on a creature, it doesn’t electrify the surface it’s standing on, but when cast directly on the surface, it does. So shocking grasp is working fine, but also on that note, electrified water should probably not stun a creature since the stun condition is pretty powerful for a cantrip, and maybe not being able to cast reactions would be more balanced (specially considering how lightning bolt will probably work). [EDIT] It turns out that shocking grasp DOES electrify water puddles under the target and apparently it never happened to me before as a bug (a welcome bug in this case).
Thaumaturgy – This cantrip has underwhelming animation. I expected it to light unlit torches nearby or at least make a sound when cast, but I guess it works fine, aside from not being able to cast it during conversations. [EDIT] Actually it does not seem to give advantage on performance or intimidation rolls in conversations.
True Strike - The tooltip needs work, since it says the buff will be applied for 2 turns, when it’s actually just one. This is also a reflection on the saving throws being rolled at the start of turns, since the “on turn” effects are happening at the start of turns rather than at the end.

2) Level 1 spells
Animal Friendship – This spell works fine, but it really should be castable during conversations to make it a little more useful, especially how many conversations are triggered from just approaching a creature.
Armor of Agathys - The “on hit damage” should not disappear when the temporary hit points are lost. This is making this spell really underrated, considering how the warlock’s “Dark one’s blessing” already gives more temporary hit points than this spell, and it should actually replace the temporary hit points given by it (the highest amount of temporary hit points should always replace the fewer ones).
Arms of Hadar - This spell works fine but has really underwhelming animations. I expected to actually see the tendrils of dark energy.
Bane – Aside from being a “control spell” mentioned in the first topic, and therefore suffering greatly from being nearly useless and very hard to maintain concentration on, this spell also needs rework on the targeting system. We should be able to choose which creatures to debuff, one by one (much like scorching ray) instead of characters just being picked randomly in a great circle area.
Bless – Similar to its negative counterpart “bane”, bless suffers from being hard to maintain concentration on, even on your 21 AC cleric with 16 constitution, since he will probably be hit by a fire surface, forcing him to make 2 concentration checks (one when hit and when he starts his turn), or otherwise be shoved or knocked prone and automatically fail the concentration check. Also, it suffers from the same targeting problem that bane has, as we should be able to pick which creatures will be hit (hell, I might even bless an enemy, why not?).
Burning Hands – This spell works and looks perfect to me. No work needed.
Charm Person – While I understand most of this spell’s uses in combat are gone since it is impossible to translate how many things you could do with it in a TTRPG, this spell feels VERY useless at the moment. If we could at least cast it during conversations, it would at least make it useful for those encounters.
Colour Spray – Works fine, but the animation is really boring. The lightning effect on bless or warding flares seems more appropriate for this spell’s description.
Command – I like how Larian handled this spell since “halt” is pretty much the most used command for this spell, although I think it would be nice to prompt the option UI and let us choose from other stuff like “drop”, “approach” and “flee”, which seem to be pretty easy to implement (especially flee, since dissonant whispers does it already).
Create Water – Works fine, but maybe it should become a cantrip if fire surfaces remain how they are at the moment, due to how many times we must cast this. [EDIT] Perhaps it can become a bonus action instead, to make it worth casting. Losing your action (and therefore your turn) to remove a small fire surface, that will probably be added again next turn is just not worth it.
Disguise Self – I love how Larian handled this spell. I was really impressed it even made it to the game and I understand how difficult it is to implement this on every conversation. There are a few bugs in game with this spell, especially when using it to interact with companions (they just ignore it and sometimes the spell even drops off). I know this is asking for too much, but maybe we could disguise as some other humanoid races, aside from the playable ones (although I think this is already being implemented).
Dissonant Whispers – I like how it was implemented and at least to me, it works perfectly and is balanced.
Ensnaring Strike – Works fine but it also suffers from the difficulty of maintaining concentration on spells due to how bounded accuracy is being ignored, as mentioned before. By the way, this is one of the few spells that actually deal damage at the START of the turn and not at the end, it is fine because it was balanced this way.
Expeditious Retreat – I don’t think I’ve used this spell once, so this is one I cannot give feedback on, although I think having 150+ hours of gameplay and never have used this spell once already states to its usefulness.
Faerie Fire – Works fine but it does suffer from the difficulty on maintaining concentration problem mentioned before. [EDIT] However, due to how easy it is to gain advantage on enemies, because of backstab and high ground homebrew rule, this spell is probably worthless.
False Life – At the moment this spell has conflicts with all effects that also give temporary hit points. I am aware that temporary hit points do not stack, and it really should not, but the wizard’s abjuration shield should not be considered a temporary hit point source and should not conflict with this spell.
Feather Fall – This spell works perfectly. No work needed here.
Find Familiar – Works fine, but personally I think a leash should be added, as the familiar walking around limitlessly really breaks immersion, especially how it sometimes triggers combat where it shouldn’t and doesn’t where it should. Also, more options of critter should be added (although I think this is already being done).
Fog Cloud – This is another spell that is really hurt by how hard the game makes to maintain concentration on a spell. Aside from that, it works fine but should really be dispelled by wind (maybe a thunderwave should dispel it).
Grease – Works perfectly but it is too powerful at the moment, due to how prone works, as mentioned before.
Guiding Bolt – This spell is perfect in every way. Love it.
Hail of Thorns – I understand the change to action economy made to implement this spell in a way that is similar to dnd 5e, but it is just not translating that well. In dnd 5e, you cast this spell as a bonus action and the next attack you make with a ranged weapon will create the spell’s effect. Having this spell cost an action plus a bonus action is just not the same thing and really makes no sense, especially knowing that this spell is not really that powerful so making it cost just an action doesn’t seem to break balance that much, as it would still cost a spell slot. I guess it’s ok but I personally don’t like how this looks.
Healing Word – Works fine and doesn’t need any work.
Hellish Rebuke – Regardless of how buggy reactions are at the moment and this spell seems to trigger the reaction but cause no damage to the target, I really hate the animation on this spell. I don’t understand why it was changed from the description in dnd 5e, which is “the creature is momentarily surrounded in hellish flames”. Right now, the spell seems to target the creature with a beam of fire that is fired from your character (which, by the way, seems to be the reason why the spell doesn’t hit the target, since the projectile is being stopped by pathing or objects in the way). It would be cooler and much simpler to just spawn flames around the target and be done with it.
Hex – Works fine but I would really love if the prompted window had keybinds, due to how often hex is cast. Also, this spell is one the easiest to suffer from the concentration difficulty mentioned on other spells and on the first comments, since it is pretty much always being concentrated by the warlock (which is the most targeted character aside from wizards).
Hunter’s Mark – Similar to the problem faced with “hex” by warlocks, this spell suffers too much from the difficulty added by the game to maintain concentration on spells, due to constant push/prone mechanics and surface/unavoidable damage that ignore the bounded accuracy rule.
Inflict Wounds – Works perfectly and I love it.
Jump – I guess it’s fine, but probably too powerful when paired with how the “jump” action works at the moment.
Longstrider – Works fine but I think the animation on this spell is too flashy, especially considering that it is always active on the character.
Mage Armor – Perfect. No work needed here. [EDIT] Maybe, only maybe, the animation on this spell is also too flashy and can be toned down, but that’s just my opinion really.
Magic Missile – The only problem with this spell is how it was turned into a projectile spell, adding the chance to miss a missile due to pathing issues, which should really not exist on magic missiles since it was the go-to spell when you want to ALWAYS hit. This is the one spell that always ignored the bounded accuracy rule, and for some reason you guys added a chance to actually miss a spell that was meant to never miss, and it really baffles me as to why that is. Please just make us choose a target for each missile and if the animation needs to have the actual projectiles, just make them ignore pathing and clipping or any target in the way.
Protection from Evil and Good – Very useless spell right now. I could be better if concentration is not easily lost. Maybe just remove the concentration from this spell and make it last 10 turns or something like that (that is if no changes are made to concentration checks).
Ray of Sickness – The only problem with this spell for me is that the tooltip says it lasts 2 turns, when it actually only lasts one turn, but that is also due to the problem that the “on each turn” effects are happening/being counted at the beginning of each turn, instead of the end.
Shield of Faith – This spell is the perfect example of how hard it is to maintain concentration on spells in BG3. Shield of Faith is a spell that was cast by nearly every cleric on pretty much every combat encounter in dnd 5e, and on BG3, me and my friends nearly never use it because it is mostly a waste of a spell slot since you will certainly lose concentration on the spell in one or maybe 2 turns, either to a fire arrow/bomb/barrel/balloon/bottle thrown by an enemy, ignoring your AC or maybe an exploding thing or jumping minotaur that will knock you prone and not allow you to even make a concentration check. So this is just worth noting on this spell because it shows how breaking balance on a small thing can turn one of the best/most used spells in the game into a waste of a spell slot.
Sleep – Again, the tooltip says the spell lasts for 2 turns when it only lasts one, since at the START of the creature’s second turn, it will get up. I guess I’m ok with the change made to this spell from the dnd 5e version, since sleep was way too powerful of a control spell for a 1st level spell (due to how long it lasts, not needing concentration, targets can’t make a saving throw, and the unconscious condition guarantees a melee critical hit). However, I do not like how many enemies can (and do) cast it at our party and I think we should also be able to pick which targets will sleep, although for some reason the targeting on this spells seems to work better than “bane” or “bless” because the game apparently always knows who I want to put to sleep.
Speak with Animals – This spell works fine and I don’t think it needs any work. [EDIT] Actually, it should also be added to the list of spells that can be cast during conversations.
Tasha’s Hideous Laughter – This is one “control spell” that is terribly hurt by the fact that saving throws are being rolled at the start of a creature’s turn. If you cast it on a creature that has 50% chance to be affected by it, this means you will lose your action and spell slot and even if you do control that creature, it will have another chance to escape from your spell before it loses even one turn, making you lose your turn and spell slot for nothing, while the target had virtually 2 chances to escape from your spell before it even took effect. Since this spell causes no damage, it is the perfect example of how this change hurts these “control spells”.
Thunderwave – Works perfectly. Me likey.
Witch Bolt – This spell is not only hurt by the concentration problem mentioned many times before, but also by the fact that Larian changed its duration from 10 turns to one turn (the tooltip says 2, but it is actually just one – as also mentioned before in other spells). So this spell has gone from a “meh” spell to a terrible spell, which just wastes a spell slot to potentially deal 1d12 damage, what can also be achieved with a cantrip that always hits or another one that deals slightly less damage but has a very high chance to control the target for at least 1 turn.

3) Level 2 spells

Aid – Perfect in every way.
Blindness – Right now the tooltip is misleading since it says the target makes its saving throw at the end of each turn (how it should be) when it actually makes it at the beginning, making this another control spell hit by the unnecessary change to the balance of spells. Also, I think the “deafness” aspect of the “blindness/deafness” spell could be added to the spell as a prompt window like other spells have and deafness maybe gives the enemy the “silenced” condition or some similar condition.
Blur – Aside from the concentration being so easily lost as explained before, the spell works fine and I really like its visual effect.
Darkness – This spell works but its best functionality is its synergy with the warlock’s “devil sight” invocation, and that is currently not working in the game.
Darkvision – Works fine. No work needed.
Detect Thoughts – This spell is very close to being completely useless. It has a gigantic potential for conversations throughout the entire game but nearly no character reacts to it at the moment and I think it would be really hard to implement this in the game unless an option is added in specific conversations, allowing a character that has this spell prepared, to cast it during the conversation. Otherwise, we will have to save scum before every conversation in the game to find out if a conversation will or not react to detect thoughts.
Hold Person – THIS ONE. This spell is my biggest rage with the way saving throws are being rolled at the start of turns. This is probably the best “control spell” in dnd 5e (aside from hold monster, but we’re talking spell slot economy here) and in BG3 it is just “meh”. I mean, it is sometimes worth risking it even in the state that the game is now, since paralyzing an enemy, for even one turn, is the same as killing it when you have melee characters on your team. But still, every time I waste my turn and my level 2 spell slot and get the enemy get paralyzed, only to watch it free itself at the start of its turn and act normally on its turn, it makes me want to quit the game instantly. PLEASE I BEG OF YOU LARIAN, FIX IT.
Invisibility – I like this very much, but I do think enemies should still be able to detect us by sound. Off course stealth could still be rolled to determine if they hear us or not, but this spell being an instant and unavoidable way to disappear from the enemy’s perception is too powerful, especially when considering how “greater invisibility” could be implemented, and that it would probably be the most powerful spell in the game if its invisibility aspect works in the same way that it is now.
Lesser Restoration – Very underwhelming spell right now. I only used it to cure the annoying disease at the bog, but honestly taking a long rest would do the same, and since long rests are limitless, this spell (and any other out-of-combat healing) is pretty useless.
Melf’s Acid Arrow – Perfect spell. No work required.
Mirror Image – Works beautifully and I love the animation on this spell and really wish it would be applied to “invoke duplicity”.
Misty Step – Also love this spell in almost every way. Personally, no changes required on this one.
Pass Without a Trace – This spell is bugged at the moment, giving a +10 to all skill checks while active, but this has been reported many times before. Also, if no changes are made to how hard it is to maintain concentration on spells, I think this spell could benefit from removing the concentration requirement, as it is mostly an out-of-combat spell that has a very long duration, and it shouldn’t hurt its balance.
Prayer of Healing – I only cast this spell once to see its animation (which is fine). It is useless, especially when considering how limitless resting is and how easy it is to heal your party with just food.
Ray of Enfeeblement – A “meh” spell in dnd 5e turned into a terrible waste of a spell slot in BG3. This is due to how easy it is to lose concentration on spells, making this spell one of the worst options on how to use your action on your turn. One good example of this is that this spell would be somewhat useful on the minotaur encounter, for example, but due to the fact that the minotaurs shove and prone you so often, you will most likely lose your concentration on this spell without having even a chance to make a concentration check.
Scorching Ray – Works perfectly in my opinion, and would be even better if cantrips weren’t so damn overpowered right now. Sometimes (too often actually) it’s better to just cast a firebolt instead of a scorching ray.
Shatter – It works mostly fine, but it is bugged and currently doesn’t work with the “sculpt spell” trait of the evocation wizards, which is a shame as it has great synergy with this spell.
Silence – I guess it is working fine. I only think conversations should not be able to start in the silence area (unless with a telepathic creature). I saw in a feedback that it should also stop NPCs from calling other NPCs from afar, and although I agree with it and see how hard that would be to implement into the game, I wasn’t able to try that anywhere in any of my mane runs.
Web – Works fine for me. I don’t think it needs any changes, but I would love to see it create web bridges.

4) Other spells and abilities
Action Surge – Works fine. No work required.
Blessing of the Trickster – I don’t think this should require concentration, and although I love the eye animation it has, the shadow part of the animation is too overwhelming right now and should probably be toned down.
Colossus Slayer – It is bugged, causing the extra damage even when the creature has full hit points, and I think it also triggers more than once per turn.
Cunning Action – Personally, I think most of the bonus actions should be added to this feature (like hide, disengage – which should be separated from jump, and so on) and those should become regular actions for everyone else. I would love to see that sweet balance brought into BG3.
Giant Killer – Haven’t tested this one out yet, so I can’t say if it works or needs any changes.
Horde Breaker – Also haven’t tested this one yet, but from what I’ve seen in other gameplays, it’s working fine.
Invoke Duplicity – When I first cast this I thought it I confused it with the minor illusion cantrip, since they both create the same visual effect. Then I cast it again and saw that the spectral scarecrow was actually the invoke duplicity. This is probably the animation I hate the most in the game, as it looks like a bad joke right now. Not only that, but the functionality is also terrible, since you cannot move the duplicate. Please make the animation somewhat closer to the mirror image effect, because it is the closest we have to a duplicate of the character right now, and also let us control the duplicate (maybe create a “pet” like mage hand). Also, if Larian really plans to keep concentrating spells as hard as it is, this is one feature that can lose its concentration requirement without breaking balance too much, since it already uses a very limited resource (channel divinity) and doesn’t last very long.
Mage Hand Legerdemain – Aside from creating an invisible mage hand, there is really no difference from a regular mage hand. Besides, just being a githyanki already gives this exact same feature, making it very underwhelming. Additional functionality should be added to this mage hand, such as pickpocketing and interacting with objects. [EDIT] This feature should also add “mage hand” to the rogue as a free cantrip, without making you choose it.
Preserve Life – Works fine but looks a bit too similar to prayer of healing. I’m ok with it though.
Second Wind – Looks good to me, with no changes required.
Sneak Attack – It’s a little bugged right now. It sometimes doesn’t add the damage even when you have advantage on the attack. Also, it almost never recognizes when an ally is within 5 feet of your target. Always works on backstabs though (which by the way needs rework, but that’s for another feedback on combat).
Speak with the Dead – I really don’t like this spell right now. When it was advertised in gameplay videos during the year it showed us a completely different version of this spell, that prompted an actual cinematic and it looked amazing, opposed to how poor and anticlimactic it looks and feels right now. At the moment, I don’t even bother casting it anymore, since all conversations created by this spell led me nowhere and gave me no useful information.
Summon Beast Companion – I guess this feature is fine, aside from the fact that the giant spider feels very unbalanced when compared to the other beasts, being the clear best choice of all beasts for everything (even tanking). Also, the wolf looks a little bad, being close to what the hyenas look like.
Superiority Dice – All maneuvers worked fine for me and I don’t think they need any work, although Riposte does disappear from your reactions bar and there is not way to add it again, so you basically “lose” this feature if it happens.
Warding Flare – Absolutely love everything about this feature. I know many people are giving negative feedback on how reactions are working, but I really like how warding flare was implemented and don’t see a problem with it right now, since the limit on how many times you could cast it between long rests was removed to balance the fact that you can’t choose exactly on which attack you want to use it.