Disagreement between who ? those waiting for a BG game, those waiting the new larian game, those waiting for the new D&D game.
BG1+2 fans, most or all of whom played and formed opinions of those games before BG3 was announced. Sorting people into groups based on their opinions doesn't change the fact that there are differing opinions.
You're right, but maybe this can help you understand why nearly everywhere consumers talk about BG3 is not a happy place Whatever you know it or you don't care, that's another point.
I think you're not totally right or totally false about nostalgia. BG was created when games were different than now. The industry was not the same, the players were not the same, the "age" was not the same. This doens't mean that the receipe can't work now. Old School RPG show it to us. Their public is not only old fans, but players that love playing another way. That's what I expected and that's why I was so hyped when I learned Larian had the game in his hands : the mix between an "old school way of playing RPG" and the larian's touch, including new macanics, graphics,...
I read somewhere on the forum something I find interresting.. Someone said something like in BG3, you'll probably have a story telling more "impressive", with video during dialogues, events, something more like a film... But the inconvenient of that is that you'll have less choices to create your story (This is probably not the right words, but this was the idea).
That's what BG is according to me : a story... YOUR story in a really coherent and "real" world. It's not about "accessibility", multiplayer,... It's not only about gameplay and visual effects, it's about your imagination, the way you want to do things in the story. This freedom, this explorations, this sensations you're in a real rude world you have to deal with, you don't really find it in new games. As said before it's hard to explain because it's all about feelings...
And this is where I don't totally agree with nostalgia because it don't think it should always be the only way. This is just how it is NOW, because no one try something else at the moment and because they are receipe that actually sells well so, why to try something else ? I'm convinced that a real modern BG-like game could be a great sucess... This is just not the way Larian and WoTC took for BG3.