This would be a lot more interesting thread if you had provided some examples sandmoth. As it is, it's pretty pointless. FYI, one of the main reasons that people already quit is too much change.
So there's that.
The cake is now an alternative fact.
Just went to the OP's profile to check him out and it says "sandmoth12 has not made any friends yet" with posts like this no wonder...
I think they'd lose as many subs as they're "potentially" gain, if not more. A new combat system isn't going to be the type of feature that will attract a bunch of new players, and I know I can say for myself, if I wanted to learn a new combat system or completely learn a new class, I'd reroll or play a different MMO.