As usual, +1 to everything @Topgoon said. We're definitely not the same person posting from different accounts. XD
I mentioned in my descriptions that improvements and adjustments could be made to RAW, as long as Larian attempts to preserve balance and depth in the action economy, class identities, and combat strategies. I don't think these things are preserved currently, and the easiest solution is to just include more of the PHB. Of course I want the developer to make improvements, but ignoring the core rules and ending up with a shallow, imbalanced game system is not fun or rewarding to play. I don't think the changes that have been made have "improved" combat.
It sounds like you don't trust Larian to make changes and you'd rather have 5e RAW rather than what Larian has come up with. Which is fine (at this point in time I also would prefer full 5e RAW), but I think it's better to advocate for specific individual changes rather than tell Larian to remove all of their hombrew. I like some of their changes after all.
The +2 Highground bonus is great imo, as is the concept (not the exact implementation) of weapon skills. A widely held opinion is that the base version of 5e's Fighter should have access to all of the Battlemaster Maneuvers, which is kind of what the weapon skills do.
Enemy damage resistances is one of the things Larian
could have copied from DOSII that might improve D&D combat. As Topgoon suggests, instead of resistance=50% and immunity=100%, BG3 monsters could have anywhere from 0-100 (200?)% damage type resistance. Perhaps then attacking with a magic weapon would halve that value (or subtract a flat percentage to a minimum of 0%).
