I think no one really argue about Larian's content. Their mechanics are great and I guess all those that bought BG3's EA were enthousiast. The actual problem and why so many people complain is that because their mecanics aren't integrated in D&D but D&D is integrated in their mechanics...
Just to give 1 or 2 exemples : They solve the "you miss a lot in the tabletop" decreasing the AC and increasing the ennemi's HP. On the paper, it work and it's still balanced. In game, it leads to many boring and even slower combats. "Powerfull low level" spells / skills can't OS a single goblin and many of them are become useless (sleep). You're hit chance is better, but the combat's aren't faster , many D&D possibilites are now useless and the combats are less tactical than they should be. The only positive thing about all this is that the player see 75% instead of 50%...
They also add verticality, which is awesome but the way they did it is bad because verticality is actually not an option. It's the same about backstab and jump/disengage. A consequences is that playing melee character actually really suck.
All their stuff are really really cool but not that way. In the end, they don't give lots of system to players, the entire game become the systems....
Adjusting some spells isn't a big deal. Some spells have already been modified like a sleep. Now it has consistently 33 hp(maybe), which is not far from the maximum possible throw. It can always be increased if necessary.
A lot of things need to be improved, but I have the impression that some people on this forum criticize every slightest deviation from the rules without considering whether the game will actually be better without any changes. I would prefer it not to be the only big dnd game in the next decade, so if they have to change something for the game to sell better, they better do it.
If the goal is that players miss less often, I guess it would have been easier to add a +4 bonus to every attack roll than adjusting everything because they changed HP... They could also have add +x to attack roll if you're higher instead of using so many advantage everywhere in the game.
As Khalid said, it's not only a spell or two... It's the entire experience that has been modified in many ways. Another issue is burning hand and all "contact" damage spells... I guess nearly no one use those spells because they are really weak... this is not because of their "systems", but because of the way they implement them.
I'm not a P&P player so I don't really care about the game being absolutely accurate... But "I know" (probably not everything) the rules and the more I think about it, the more I think the game would be far more fun, tactical, balance and so on if they started to create a D&D game in which they'll implement their systems instead of thinking about how they could implement D&D in them...
If this would be so easy. If they leave the AC reduced and restore the original HP, many of the fights in act 1 will become terribly easy and boring at the same time. In RTwP, you can easily fix this by adding extra mobs that you can't do in a turn-based game. Turn-based games are poorly suited to fighting a mass of weak enemies.
I never suggested that they leave the AC reduced and restore the original HP.
Did you read the link Khalid gave you ? Do you know that Larian's changes about AC and HP has nearly NO consequences on the difficulty of combats and the number of turn to kill ennemies ? It just increase your %hit and nothing more... In the end the combats are the same exept that many spells and skills become totally useless.
Do you really think changing every monsters abilities AND many spells / skills / classes / ... to give us the FEELING that we are more efficient in combat is a good way of doing things ?
And as Vaell said just above... I don't think why you're talking about adding creatures to encounters. There are way more things that can be done to increase/reduce the difficulty.
Actually the game is often inconsistent and too hard for a normal game mode. This is also partly because of Larian's homemade rules. Think about newcomers.