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.
A bit of civility and respect for others opinions goes a long way toward getting any respect in return. Overly hostile, profane and insulting posts are a sign that people don't really have anything to say. Profanity is best served out in very small doses.
"Forum drama exists because people enjoy creating it." - ML/2013
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.