MMOs anymore can't be about "what's new", it can only be about "what twist can we put on an old formula". Innovation is the factor here, since there's really nothing "new" in these cookie-cutter games.
And if one is not so keen on the innovation factor ("it's all the same, nothing new"), there's always the opportunity to start over in a new game with a clean slate. Sometimes that's the most exciting part about a new game - people who like to be competitive can now become competitive from the beginning instead of having to start behind everyone and staying behind.
To note, however, I think MMOs anymore can maybe pull new features and systems from older console RPGs. Some games like Dark Cloud for the PS2 would make great MMOs, but need either a refined or polished system and content that reflects an MMO-genre game. We already have DWO and MegaTen, both hosted by Aeria, but others could be adapted too, and certain others that have been attempted (*cough*Ys: Call of Solum*cough*) could be revived and re-marketed to a whole new user base. Heck, even Mega Man has an online game coming out in Korea.