Personally I'd love to see a multiplayer TES, or Fallout game - but only multiplayer, no MMO bullhickey. Wandering the wasteland is often a lonely endeavor, having multiplayer in Fallout3 for instance, would mean I'd still be playing it. Same could be said for Skyrim, but I dunno - TES always striked me as a strong single player game series with no distinct need for multiplayer - it would be nice, but it's not a deal breaker.
The current suite of MMO's out there are dull as hell, people are running towards their next grind quest, running back from their next grind quest, or standing around trying to look impressive. Theres huge scope for games like Borderlands, where having 3 buddies to play with adds to the game, it doesn't become the game.
I they announced tomorrow that Fallout4 is being developed, and it'll have co-op multiplayer ala Borderlands, well I'd be as happy as a bug in a lug - I'd actually do that ''throwing money at the screen but nothing happen'' gag.