Quite frankly, I have a small list of things that would have to change in order to bring a lot of the actual tactical decision making into the game.
1) Turn high ground advantage/low ground disadvantage into +2/-2 modifiers. Maybe even get rid of the -2 modifier entirely. 2) Turn backstab advantage into a flanking system instead, and reduce the modifier from advantage to +2. 3) Allow saving throws to mitigate damaging field effects and items such as barrels. Field effect damage should additionally not trigger concentration checks. 4) Add ready actions and proper reactions to the game. One can talk about how cumbersome reactions may or may not be, but ready actions don't have that problem at all, and I don't see a valid reason why ready actions at the very minimum should be absent, unless the engine really is as non-flexible for programming anything new outside of environmental stuff as people are starting to believe.
They also need to add +2 cover AC against ranged attacks for enemies engaged in melee combat, and decouple jump and disengage, make them cost an action, and provoke AOO, and implement push as per 5e rules instead of their hulk push.
This is all wishful thinking though, I doubt Larian is backtracking from their insistence on including DOS mechanics in BG3 as much as possible.