What classes are only 2 buttons? I'd like to play those.
While I don't overly care if we get new classes or races most of the time. I also don't really see the problem with getting a new class\race. I've played in TBC, and there has always been complaints to nerf class X, because it's too strong in raid or PvP. So whether we have 5 classes and 5 specs or 20 classes and 150 specs, there is always going to be a group somewhere complain their class (but really spec) is too weak compared to whatever other classes beats them in the meters that week.
I am person that prefers lots of choices over little choice.