My opinion is: BG3 would profit from being more DnD and less DOS.
I never finished DOS2 because I did not like the combat system: The whole screen was on fire all the time.
I did not like the armor system and I did not like how numbers scale with level, so the numbers of stats and damage almost doubled on every level up.
So I am happy for the change to DnD and I dislike lots of changes made to DnD, like the shove madness.
It helped fight the stat inflation a bit, I don´t think we have enemies with several 1000 HP. (at least I hope so, I have not finished it yet)
My opinion is, that throwing 3 fireballs per turn or using 6 attacks with smite every turn, then rest and repeat is not interesting gameplay.
Making concentration or CC close to useless did not make the game better.
In my opinion larian still "suffers" from its early successes.
I also think BG3 would profit from being D&D all the way, and just be a better game for it. That doesn't remove the possibility of having difficulty modes that would ease some of those rules and restrictions for more casual play.
D&D is, or would have been, such a breath of fresh air in (video) gaming where both players and devs seem to be conditioned to MMO-style mechanics, big numbers, cool downs, loot grind, flashy abilities that do next to nothing etc. BG3 still suffers from that, although I guess we should be glad that Larian kept
most of D&D. I think you're right in that the success of DOS 2 hinders Larian, too. That system is far from perfect and in my opinion much worse than D&D overall, even for a video game. But they are clinging to it tooth and nail and don't seem to understand what is great about D&D. Sometimes less is more, like with magic items. There is too much useless magic junk in BG3.
There seems to be a deliberate attempt to dilute the classes towards a more classless system by sharing their abilities. Scrolls are a great example of this. I don't think folks over at Larian understand that what makes a Wizard cool and unique to play, is just as much what the other classes can't do as what the Wizard can do. The fact that the party Barbarian can't just pick up a scroll and cast the same spells makes a spellcasters feel special. What makes a Rogue fun, is the fact that the party Paladin in Plate Mail can't just sneak just as well as they can. But in BG3 they can as long as they stay out of some gamey vision cones. Larian ignored or didn't understand that multiclassing already exists to blur these roles and abilities to make it possible in a balanced way.
Every class being able to do everything is not a good goal. Especially in a party based RPG.
Speaking with the dead, or animals. Unique abilities available to a multitude of races and classes. But these abilities are completely overshadowed by the fact that the player is basically being showered by scrolls, potions and amulets that give those same abilities to anyone. It's already very likely without those items that someone in the party can do those things. Yeah Larian, we get it that you want us to use those cool abilities you put in the game. But they don't feel special anymore, it's more like something everyone does and is
supposed to do all the time. By handing out such easy solutions you diminish the rewards. How cool would it be on a second playthrough to discover an entire world of speaking to the dead or animals, if you didn't have a Druid or Cleric in the party the first time around. And why is Dror Ragzlin casting Speak with the Dead, when you have Priestess Gut in the next room? Why do you need scrolls for such abilities when characters doing class appropriate things would be a good opportunity to flesh them out?
I suppose being able to cheese encounters with barrels and shoving is actually fun for the casual player who doesn't want to learn the rules. But there are players who would prefer to be completely challenged by resource management and such without ANY cheese, and it sucks Larian can't provide a proper D&D experience for those players.
Still hoping for a definitive edition of BG3 that will follow D&D more closely.