I'll be fine with just a D&D hardcore setting like in other D&D CRPGs. It's a bit of a tradition since BG1.

I don't think a switch for every little feature is worth the effort for the devs. Like with height advantage I don't think either on or off is the right way, but rather nerf the impact of high ground instead.

They are professional game devs. It's up to them to provide a good experience to both D&D veterans and casual players without putting every feature behind a toggle.