Right now my priority list is the following.
1) High ground advantage/low ground disadvantage changed to +2 AC attacking from low ground to high ground
2) Backstab advantage nuked or changed to some kind of flanking system
3) Bonus action Disengage changed to standard action (note that I did not say bonus action Jump, I think Jump should be left alone, it's the Disengage part that is the real issue)
4) Threaten range being too large (should just be tied to whether or not an enemy is able to opportunity attack), and get rid of 'Target Too Close'
--Probably optional if the above four are addressed first--
5) Bonus action Shove changed to standard action
If Larian is able to get player controlled reactions and ready actions into the game, I'd place them between number 2 and 3 on my list.
This. This mirrors my priority list 100%, i cannot agree more.
I think most of these would not be that problematic to implement and add a toggle for and looking at most common complains around combat on this forum, I think it would be a popular move to do.
I think to able to do small tweaks to gameplay is even more important for a game designed to be played multiple times.