I don't mind the graphics, so I guess I just can't comment on that. Have you actually finished the single player?
The main thing about SCII is pretty much the bottomless pit of competition and an extremely high skill set that you can never max. So much to do with this game, even as an observer.
But if you don't like it you don't like it. I find it amazing because I am a competitive guy and naturally pretty good at games.