Because, in my personal opinion, D:OS2 isn't very good, and more importantly, I didn't enjoy playing it. So as a Baldur's Gate fan, and Baldur's Gate legacy fan (later bioware games, Obsidian etc) I don't want to see that stuff in BG3. Just as I don't like Bethesda Fallouts, while being a Fallout fan (1&2&New Vegas).
I can understand as to why you're disappointed with the choice of developer then but:
1) That ship has sailed
2) It has nothing to do with the sequel name being justified or not
Larian has their style, obviously not everyone will like that style. You can't ask a dev to throw their identity out of the window though.
I am actually not disappointed. Personally, I didn’t want BG3 to happen at all - the story is finished, and is very much a product of its time. Making a sequel that I would fully embrace isn’t impossible, but would require a very fine direction, to be both fresh and faithful to the originals.
Hearing that Larian will be doing BG3 I thought to be a good idea, as what I felt what D:OS2 was lacking was better systems and better tone. I underestimated, however, how little D&D the game will feel. They get served a straight up better system to use for their titles, and they look for ways to break many aspects of it.
