I hope not. The main TES series is a single-player game and should stay that way. There are rumors that a affilated Zenimarx company(Beth's parent company) are working on a TES MMO so.. I guess that'll satisfy the co-op audience.
The devs can spend their time adding other more important features to the game.
it's better to have a completely awesome singleplayer only game than a half done game with co-op. if you want co-op go play WoW or something. i hope for a long and epic g.ame