I wonder when we will get the first truly successful console MMO. Personally, I think that the first game to get the "console" part correct will be the game that beats WoW's subscription numbers.
But I wonder what that game will look like, what will make it work? Will it be entirely voice-comm based? After all, Mass Effect is a console game, and The Old Republic is very similar.
I think the key element that needs to be worked out is multiple players in the same household. For computer MMOs, every player has their own computer. But that usually isn't the case with console games. Would the MMO have some sort of co-op mode, where if two players are in the same area, they appear on the same screen? And then seamlessly split screen if they split up?
I have no idea how it would work. But I'm sure there are game companies working on it, and it will be interesting to see what they come up with.