This is one of the few game settings that actually has a chance at getting something like WoW's numbers, assuming that the gameplay is equally sticky. World of Darkness has huge numbers of fans, perhaps not as quite many as Star Trek, but they're far more game-oriented and FAR more fanatic on average.
What I'm not so sure about is CCP's ability to turn out a game with such broad appeal. I don't think that targeting an audience of griefers is going to make it. And taking two years after release to make the game fun (like they did with Eve) isn't going to help them reach millions of players either. It needs to be fun right out of the gate...I guess we'll see if they have what it takes to do that.