User blog comment:MarkvA/Skyrim's Most Wanted Features and Fixes/@comment-108.202.196.86-20111206081745/@comment-2081141-20111207020047

Not every game needs co-op. After all, how the heck would you run it? Like Fable, where you jump into the other guy's world? Either you wouldn't be allowed to take anything in or you wouldn't be allowed to pick anything up while you were there (so you don't steal unique items), and in addition the game would quickly lose its challenge.

Co-op would be cool, but only if it was something like individual dungeons or castle raids, because a full co-op is too hard to implement.