You know what? I don't mind the small community. Sure, you sometimes have to wait a while for games to fill up, but on the flip side you actually get to know a lot of the people who play online, and build a reputation yourself.
Now, I will totally agree with the balance statement and the issue of beginners getting into multiplayer. I've long since learned that there are two ways to pick up a multiplayer RTS game: learn the hard way and take your beatings in stride, or spend many hours scouring forums for the sage advice of experienced players. I personally make the effort to be patient with newbies, but it's easy for them to be discouraged.
As for balance, all games have their balance issues, and to be honest it's a lot harder than it looks to get things just right.