Fair. However, they are based on the 5e rules. They may not be a 1:1 implementation of them, but you can very clearly see the rules have been implemented, even if they have taken some liberties with them. It doesn't matter which rules they changed in a video game adaptation, there was always going to be someone who complained about that specific rule.
That might be true, although I can't recall anyone complaining about Speak with Animals lasting until the next long rest or concentration break. For the most part though, people are complaining about changes because of the effect the changes have on balance. Efforts to further balance the changes with more changes is only creating the need for further changes. This can go on indefinitely, eating up development time and resources.
The question then arises, are you required to rest after every fight in the EA? The answer to this btw, is very clearly no. In my current solo play through with a Warlock, the first time I rested was after clearing out the temple to Jergal+ all of the bandits in there. This is in a 1 player play through, where I have much fewer resources available to me. In the very first play through I did, when I was effectively going in blind, I only rested 3 times during the entire EA. There is nothing in the current EA that forces you to rest and putting elemental surfaces into the game does not magically change this.
I'm not long resting much either. That is however, because of additional changes, such as food which can be as good or better as healing potions and spells.
However, at the moment, there is nothing seemingly limiting the amount of long rests you can take. That skews the balance towards casters, who can blow all their spells in every combat. Warlocks only have a single short rest possible, so they're less attractive to use in comparison - particularly because of Fire Bolt's added strength.
Obviously this is not acceptable for most people who are playing the game, but having optional difficulty settings for this doesn't impact their gameplay, considering that you are then only opting into it if its what you want. Btw, challenge modes do not need to be "balanced" either, so long as the player's implicit understanding is that the challenge mode is going to be unfair to begin with. The Ultimate Challenge in Deadfire for example is in no way, shape or form balanced, but those of us who do try to beat it, enjoy doing so even though we know the game is very clearly stacked against us. Kingmaker's Unfair difficulty even has the name "unfair" in the title, that hasn't stopped me or others from enjoying playing the game on it.
Options and difficulty levels still need to be tested and somewhat balanced even if you slap the words "Unfair" onto a difficulty level.
Yeah, D&D's HP values are not balanced around the idea of surfaces, which means that if you want to include surfaces in the game, you also need to increase the values of monster hitpoints. This would ofc penalize non caster classes, which would also result in you likely having to reduce monster AC values, in order to act as a correcting factor. This seems to more or less match up with the system we have now. Other correcting factors can and should probably be implemented, like the saves which you have pointed out.
Player hit points and player AC have not been increased to compensate for all the surfaces enemies can throw around. Instead, they made food items you can pick up in bunches better than clerical healing, and have no limits on long rests, which make Warlocks pretty crappy with a 4-character limit in a party.
As for concentration spells, from my perspective the current situation is fine. If they break because you are standing in a surface, the chances are, its as a result of poor play on your part, because it is mostly avoidable. When I did the goblin camp in my current playthrough for example, I did not have concentration break once on hex during the entire fight. By breaking line of sight and taking proper advantage of terrain, maintaining concentration is not a problem. Basically, concentration in the current status quo rewards good gameplay. It adds an extra element of risk/reward to using concentration spells and forces a player to make more careful decisions than they would otherwise, which is imo a good thing.
"If you're standing in a surface, it's a result of your own poor play." This is an overly general statement. The maximum range on the longest range spells has been cut in half, many combat arenas are designed so that you cannot get line of sight onto enemies without being in range of enemies, and enemies have many additional surface creating effects and bombs.
When it comes to spell balance, everyone who is upset about the changes to monster HP seems to forget one thing - You can very easily adjust the HP thresholds of those spells. Double the monster HP? You can double the threshold for sleep as well. Similarly, you can make adjustments to sacred flame.
All we need to do is just change this one little thing, and that'll fix the problem, right? Until that change makes more problems apparent. What happens when we get access to the old classic Fireball, and it's a wet fart of a spell thanks to inflated monster HP? Then you need to change more things.
The domino effect of changes means that they'll need to add "other correcting factors", and then even more "other correcting factors" to correct for those changes, and later, even more "other correcting factors".
I agree advantage/disadvantage should not be provided for terrain differences, purely because it makes them too easy to acquire. There should either be a much smaller bonus for high ground (+1 or +2) to reward good positioning, or no bonus at all, because there is a more subtle advantage in terms of being able to position better against enemies from above.
I agree that+1 or +2 would be better. Or maybe a range increase like what D:OS 2 has. I had a combat where I was up in the rafters, attempting to get sneak attack from above, but despite enemies being in the circle, I had disadvantage for being "outside my normal attack range".
The rules of 5e are intended for a different design space, they are intended to make a game which is played on a tabletop. This has some constraints, for example, you cannot run 1000's of calculations for lots of small details, but it also does allow for spells like wish to exist, because you can come up with inventive and new results for the spell on the fly. If you are adapting the rules for a different design space, in this case, a computer game, it makes sense to take some liberties with the rules to better take advantage of the tools the new medium has available to it.
I defend surfaces, because they add a tactical layer to combat. They definitely need to be adjusted and aren't fine in their current form, but they make combat more interesting and better that they are adjusted than removed entirely.
Surfaces don't need to be removed entirely, they can add things, but they need significant adjustments. For starters, they are far too abundant, they require saving throws, applying them from cantrips is far too powerful (especially when a direct hit deals damage and creates a surface), and there are too many ways to create them - largely because most enemies carry tons of grenades and magic arrows for the express purpose of creating surfaces.
Except its not an edge case. I have finished the entire EA with a single character, not taking advantage of surfaces at all. I have also finished it with a party and the party only had to rest 3 times throughout the entire playthrough. And no, it wasn't because I ate stuff after every fight, its because for most fights you can either alpha strike enemies during a surprise round, giving them no chance at all to respond, or because there are plenty of environmental obstacles you can take advantage of to constrain enemies. The game does not force you to use surfaces at all, you can use them if you wish to. You are also not forced to rest after every encounter. If you can finish the EA with a single character, pretty much any party of 4 will also manage.
I don't know your exact strategy, so I am going to presume that you are abusing stealth and range to pick off enemies and run away. Especially for your solo character.
Your argument is "if you play in these exact specific ways, surfaces aren't a problem". That's a silly argument. If someone abuses mechanics and reloading enough and most fights can be beaten easily. That doesn't make it balanced for "normal" play. King Tiki explained way better than I can.
