By the way, I just wrote a feedback directly to WotC.
Sounds like a good idea.
Even if Larian insists on their innovations, it would be nice if there were an optional D&D 5e mode, especially in light of it supposedly being a D&D 5e based game.
If they made it an option that could be toggled, that would be amazing! I say this only because I pray that it wouldn't be long before a modder made a way to add an optional toggle for 3.5 rules, which I would MUCH rather have available to play by.