But I think asking LARIAN, which revolutionized turn-based 3D top-down CRPGs and permutation gameplay in the CRPG scene (where it was more of an immersive sim thing before), to be the one to drop everything and produce what everyone else is already producing is a mistake.
100%. Larian at least makes interesting turn-based games, even if flawed in some respects, but I would definitely trust them with making turn-based games more than the action-based games that they have been on official record stating that they only made because of their publishers essentially forcing them to, back in the day. Game development shouldn't be a question of whether they should, it should be a question of whether they want to.
I feel like a lot of arguments for wanting BG3 to use a more action style is basically code for 'I already know there's a bunch of other action RPGs out there, I'm just mad the sequel to my specific franchise isn't one of them'. Not much different from all the tired arguments in the Final Fantasy community about FF moving away from turn-based games when there are plenty of turn-based RPGs out there (even by the same company, it feels like SE's most well-received games from their deluge last year were the turn-based tactical RPGs while the rest aside from their attempt at RTwP in Diofield seemingly fell flat on their faces critically), and the arguments there basically boil down to 'I'm just mad that there's no super high budget turn-based FF game'.
The only argument I'd consider valid for not wanting BG3 to be turn-based is for people that want it to be RTwP on principle of the previous two games being RTwP. But even then, I don't think Larian has ever made a RTwP game before.