Adding my 2 cents I saw a couple of people wrote the game was really hard the first time they played and second playthrough was almost too easy, also watching some gameplay videos there are a fair amount of “oh I did not know that” moment in the middle of people’s playthrough so i believe overall difficulty feel will be shifted a lot for a couple of people once the tutorial is more extensive and the UI is more polished. Also as others i expect Larian to tweak/experiment with the action economy/resting system and nerf some of the existing cheese as well which can radically change the difficulty feel again.
I do like some of the ideas in OP and agree that once most of the rules and tutorial are functioing better then Larian will see more clearly from the feedback where to set toggle options and balance encounters based on difficulty levels. Regarding gameplay toggles it would be nice to see some “hardcore dnd rules” option (where it makes sense and there is demand) but we will see.
Personally im waiting for a simple (?) “cannot save during combat” toggle this made combat in battle brothers super tense because of the RNG which i like (but i understand many dont).