Whereas I can see the appeal in this I would have to say no. I wouldn't mind a co-op feature in a later game though (being realistic I know it's not happening with Skyrim).
I enjoy MMOs but as other people have said you would lose the Elder Scrolls feel if they tried. They would have to curtail the affects of your actions much more, limiting the very freedom that makes this series so enthralling as to allow others to play the game as well as yourself. The pace at which people devour content would also force any companies involved to quickly abandon many aspects of the game in order to try and turn it into a repetitious treadmill to farm players for their subscription fees, as the investors in such a project would want to see a large and continous return.
Of course if you wanted to allow PvP to appease those that would like it you would, as someone else said, not be too far from the world of Mortal Online, and those asking for TES in an MMO form would probably not want to see their character lying dead on the floor (destiny be damned!) while another hero dances on their corpse shouting insults of nonsensical drivel.
The best parts of an MMO are also by far the worst, the people.
That last sentence is so true.
If they stayed well away from the WoW model and made it very clear from the get-go, aiming exclusively at fans of The Elder Scrolls and open world RPGs in general instead of trying to grab every Tom, dike and Harry away from WoW, we would have a much better community. Add heavy moderation and and monthly, maybe even weekly, events held by GMs and you would have perfection!