UI, Controls, QoL :
Part 1,
Part 2,
Part 3,
Part 4,
Part 5.
Roleplay, Story, Immersion :
Part 1,
Part 2,
Part 3.
Mechanisms :
Part 1,
Part 2,
Part 3,
Part 4.
COMBAT : STRATEGIES, BALANCE, VARIETY
I feel as if it sounds quite irrelevant to talk about balance this early in development. Normally I would expect that fine tuning the balance of a game would happen toward the very end, once all mechanisms are fixed and the numbers tweaking process can start. But the thing with 5E is that there are very few numbers to tweak : it's all Advantage/Disadvantage. It is a welcome streamlining. But it's also pretty damn heavy-handed. Rules for obtaining Advantage/Disadvantage basically exist or not, and each addition or removal significantly affects the balance. So the game's balance can be appreciated already and won't change much unless entire rules are revised.
From a strategic/tactical standpoint,
the current mechanisms induce a balance that doesn't seem to foster variety. Ranged-combat rules. Other strategies are viable, but sub-optimal, and thus less appealing. And since enemies will take the high-ground if I don't, it is most natural to gravitate toward using it and doing ranged attacks. This makes the strategic space poorer. Notably,
melee feels as if it really wasn't given much love.
As a result, from an immersion standpoint,
the game ends up sometimes feeling like a Western or Modern/Futuristic tactical shooter. Not so much like a game taking place in a late-medieval or renaissance setting, with knights in armour wielding swords and shields in melee.
Should Backstab and High-Ground even exist ? The only basic mechanism to gain Advantage in 5E is to attack an enemy that cannot see you. On top of this, you have added two basic mechanisms to gain Advantage : Backstab (which is somehow related to unseen attacker) and the High/Low-Ground rule.
These additions, necessarily, displace the original tabletop strategic balance to a new one, which gives less value to spells and class abilities providing Advantage, and gives more value to tactical combat (positioning, manoeuvres, battlefield control, etc). Is that a bad thing ? Not necessarily, provided benefitting from Backstab or High/Low-Ground requires some tactical work and feels earned. Indeed, spells and class abilities consume resources (
Magic Points spell slots, Speciality Points, Speciality Dice, etc). The new, basic mechanisms don't. Pulling off an Advantage from them should reward good tactics, and perhaps “cost" some effort to setup. But
currently, Backstab is given for free and High/Low-Ground is over-powered.
Now, two things. Firstly, I gather that you have lowered the AC and increased the HP of some creatures like goblins, in order to reduce the frequency of misses. I belong to the group of players who accept misses, but it seems that you want your 5E homebrew to cater to players who don't. That's your vision, and adding ways to hit with higher probability goes along it. Secondly, the High/Low-Ground rule uses the verticality/3-dimensionality you have decided would be a core part of your vision. So I doubt any of these two rules will go away completely. But the precise form that they have should really be revised.
Melee combat : Backstab and Flanking. Which form of Backstab/Flanking should exist ? The current form, Backstab (which should rather be called Rear Attack or something, since you can't really stab with a mace ...), is the strongest one : anyone striking an enemy in the back gets Advantage. Repeatedly.
A weaker form would be a Flanking where any creature who has an ally in melee against an enemy gains Advantage on melee attacks against that enemy.
A yet weaker form would be a Flanking where any creature who has an ally in melee against an enemy gains Advantage on melee attacks against that enemy provided that the creature is in the back of the enemy. So if two allies surround an enemy, with this weaker Flanking, only one of the two has Advantage.
Clearly, any Flanking rule requires more effort to set up, since a party needs to bring two melee combatants in a melee and in good positions to gain Advantage. They would feel more rewarding. Meanwhile, the current rules for Backstab are too easy to benefit from and strongly immersion-breaking.
Opponents should dynamically face their enemy in melee. A creature in melee range of a single enemy should automatically pivot to always face their enemy. Without this, very annoying problems happen.
- My melee combatant casually walks around the enemy to gain Backstab each turn. This makes absolutely no sense and thus breaks immersion. Meanwhile, from a tactical point of view, there is no interesting play here. What little movement this consumes is a negligible cost. The only real risk in doing so is that of accidentally incurring an Opportunity Attack, given the current poor controls and pathing. Since melees are rarely very crowded, going around the desired enemy is generally possible. So I can get Advantage almost every turn without working for it at all.
- My melee combatant who is flanked by 2 enemies has just killed one. I now have remember to hover over the enemy in my back to force my character to face it before ending my turn. This is a quality-of-life issue, and automatic facing would solve it.
Probably, an isolated creature could dynamically face a combatant coming to melee range who did not sneak behind silently. This is a follow-up on the point above. If my Rogue loudly Dashed to the back of an enemy archer, it would stand to reason that the archer heard my Rogue and turned around. Again, the idea is that we should have to deserve getting an Advantage.
Should a Backstabbed creature not turn to face their aggressor ? A creature who just received an Backstab attack from a single melee-ranged enemy should perhaps turn to face that enemy. This way, a character can sneak and deliver one attack with Backstab, but a second attack (from the same character or a new one) will not also have Backstab.
Backstab and Opportunity Attack are currently clashing. I can come behind an enemy and attack with Advantage thanks to the Backstab mechanism. This makes some sense because I'm in the enemy's back so, obviously, they cannot see me. But if I try to move away from that enemy, even without having attacked, I receive an Opportunity Attack because, obviously, the enemy can see me turning my back on their back ... wait, what ? The two are not compatible.
I should probably not be subject to Opportunity Attack if I move away from an enemy while being in their back.
Ranged combat : High-Ground and Low-Ground rules. The High/Low-Ground rule lacks credibility. In an abstract game, rules don't need justifications other than the fact that they lead to interesting decisions. In a Euro-style, strategy board game, mechanisms typically dominate but often try to relate to the theme. DnD is a more American-style tabletop game and is strongly invested in immersion. It also has its roots in wargaming, which cares a lot about simulating real-world aspects. So I feel it is not completely out of place to ask : what does this High-Ground mechanism capture ?
What advantage will a real-life archer on top of a big rock have over an archer on the ground ? As far as I can see, the answer is : pretty much none. So this combat mechanism may not quite strongly break immersion, but it doesn't exactly contributes positively to it either.
The only advantage the high ground could realistically give is a slightly improved range. From a tactical standpoint, maybe this could be interesting. Maybe not. But I don't think it is currently implemented.
The High/Low-Ground rule is over-powered. I feel this rule should be contrasted with Backstab. Suppose the enemy and I have completely identical fighters, each with a sword.
- If I additionally have a bow, then I get a couple of attacks that go unanswered before the enemy reaches me and we switch to melee. This is the classical and natural advantage of the ranged weapon (with melee weapon) over the melee weapon (on its own).
- If we both have only swords, but I am a better tactician and manage to obtain the Backstab in the melee, then I have Advantage on my attacks while the enemy has normal attacks : that's good for me.
- If we both have a bow, but I am a better tactician and manage to secure the high ground, then I have Advantage on my attacks while the enemy has Disadvantage on their attacks : this is incredibly good for me.
- And if I have a bow, the high ground and the enemy has only a sword, I have Advantage on my attacks while the enemy has no attacks, at least for a while.
This makes ranged combat a far better strategy than melee combat. If you want to keep some form of that High/Low-Ground rule, probably, only half of it should apply : Advantage for the High-Ground attacks, or Disadvantage for the Low-Ground attacks, but not both.
Finally, there is also, of course, the option of deviating from the 5E rules (which you have already done, so it wouldn't be a first), and give yourself finer tools than Advantage/Disadvantage. Since an archer on a rooftop or behind a parapet can, in some cases, take some cover, they could benefit from a +N to AC when shot at from a lower ground. Obviously, this won't be perfect either, since there are a number of rocks (like those in front of the Druid Grove's gate), where standing and shooting from rather makes you a pretty open target for any archer lower on the battlefield ...
Ranged combat : Threatened rule. The Threatened rule for ranged attacks is quite counter-intuitive. Why should a ranged attacker have Disadvantage when they are too close to their melee-fighting target ? Maybe I'm missing something obvious, but I would assume that the closer you are to your target, the easier it is for aiming. 5E and BG3 make aiming from a long distance harder, by giving Disadvantage. I wasn't really hoping for Advantage at close range, but Disadvantage is surprising.
Now, I can see that, in melee range, not having a melee weapon means no ability to parry. This could have translated naturally into an AC penalty. I can see that, technically, a penalty to hit is also a penalty. It has the same effect of dis-incentivising me to conduct a fight in melee with a ranged weapon. But the question is : what about when I'm close but not in melee range ? If the enemy cannot swing a melee weapon at me, why should hitting it be more difficult ?
That mechanism sounds quite counter-intuitive.
The Jump in combat and Disengage. The Jump, during combat, removes a lot of the tactics of melee combat. And Disengage is currently too easy to do, making ranged combatants able to play on their terms (i.e. do ranged attacks) no matter what.
It should not be possible to Jump over enemies. Currently, even a low-Strength character can do superhuman jumps above enemies.
Do the enemies form a line to prevent me from walking around and Flanking them ? I use a Jump and I Flank them ! Do they block the full width of a corridor so I cannot get in their back ? I use Jump and I'm in their back !
Interesting melee tactics are devalued because of the Jump. Meanwhile, a very sensible ranged tactics like shoot-and-take-cover is perfectly employable.
Jump and Disengage should be distinct things. From a simulation standpoint, there is nothing realistic captured by this mechanism. It fact, it's the very contrary : turning your back on the enemy as you get ready for a (superhuman/cartoonish/grasshopper) jump sounds like the best way to receive an Opportunity Attack.
From a tactical standpoint, currently, with a Jump, we can simultaneously Disengage, get out of difficult terrain and land behind the tight enemy front line. All in a Bonus Action's work !
Disengage should probably be an Action, not a Bonus Action. At least, for most creatures. Goblins, Rogues or Monks may be better at Disengage. But that should not be the case for everyone.
At the moment, there is often little point for a melee combatant (especially one out of Actions) to finish their turn against an archer, in order to force the archer to either fight in melee (which is presumably not their strength) or "pay" their opponent an OA to move away. Whether the archer is a goblin (super common in Act 1) or a member of my party, a pure archer has little to fear regarding melee, as they are never "pinned" to it. That's one more melee tactics which is devalued.
Surfaces. This is not the biggest deal for me, but the rules for elemental surfaces feel way too generous at the moment. Elemental projectiles are like having the cake and eating it, because they both damage the target and do an elemental splash which interacts with the ground. It feels cheesy without me even trying too hard to cheese.
The reason why I'm not big on this issue is that I can easily refrain from abusing surface-based tactics : enemies don't use them too much and I can often remove barrels that are dangerous for me before the fight starts (though to be honest, doing so is often quite metagamey).
Elemental projectiles should not do area damage when missing a target. A miss is a miss. In the case of a mostly-horizontal shot, which is the majority of shots, if I miss, my projectile will realistically end its course a number of meters behind the target. Arguably, the projectile "missing" could be sometimes due to my bad aim or the enemy dodging, and sometimes due to the enemy's armour taking the hit. In the latter case, one could consider an elemental splash occurring. But that's not all the time.
From a tactical point of view, no splash when missing would force the player to choose : do you target the enemy for a chance to both activate the surface and hit the enemy with the risk of failing both, or do you target the surface for the guarantee to activate it but also the guarantee to not hit the enemy ?
Elemental projectiles should, possibly, not do area damage when hitting a target. Again, the idea would be to present players with a decision : aiming for the surface (and possibly causing a bit of fire damage on several enemies) or aiming for just one (possibly hitting it hard).
When enemies are flying, there should quite probably be no surface effect. I mean, I could understand the surface being activated if the target dies from the attack and falls to the ground. But missing an armour-less raven or imp, on flat ground, and still setting the grease underneath them on fire doesn't score very high on my immersion-o-meter.
Prof. Dr. Dr. Mad S. Tist 
