@OP are you trying to ask "Should BG3 be as close to the 5e combat rules as possible, or can there be rule changes that might improve combat?" (I'd vote for the latter because a lot of 5e rules are meh) Alternatively, are you trying to ask "Should BG3 be as close to the 5e combat rules as possible, or do we trust Larian to make any rule changes?" (I'd vote for the former because Larian's decisions so far...haven't been the best).
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.
