I never ever played 5e, but after playing solasta. They should just copy paste the gosh darn mechanics. The mechanics of the game is fun.
I have downloaded mods to make bg3 more dnd like but man that mod is not perfect and somethings break sadly. I really do not like it when mods fix the gameplay of the game. I like it when they improve it, like Long war 2 from xcom. Mods will certainly improve the game and let us have other classes from other books.
Dont get me wrong BG3 is an absolutely beautiful game but combat feels too easy once you understand the mechanics. No challenge beyond the game when you understand the mechanics right now. In xcom 2 for example in legendary, hell even commander, you only get a fighting chance once you understand the mechanics.
The mechanics of BG3 are way too easy to abuse. Backstabbing and shooting from high ground is way too easy especially with shove. Plus the high ground mechanic is buggy as hell anyways. You can get low ground disadvantage from the half ogre in the barn just by aiming your shot to its head. But if you aim at its feet you can normal aiming without disadvantage. The best advice I saw was give +2 to high ground -2 to low ground.
I would go even further, why should shoot better if you have high ground. You will just be harder to hit because of less exposed body parts. So - 2 to low ground only would be good enough. Maybe even too powerful.