The one thing that I would lament is the limitations multiplayer would put on mods. Most FPS games from Doom onward allowed for synchronization of files, but with current Oblivion as multiplayer? I'm not sure people would want to wait 30 minutes to start playing unless it was with a close friend. Some people have a laundry list of stinkin' mods going and some mods are simply daunting in size. Like Battlespire, I believe it would have to be geared for multiplayer only and not very mod friendly at all. Having said that, I still hold hope that meaningful multiplayer could be achieved in Tamriel someday. An MMORPG isn't out of the question in my mind, but it would have to be done with an engine designed for role-play... like the Hero Engine by Simutronics.