That was my biggest problem with cyrodiil too. It was very boring to look at; very little visual incentive to explore. "Oh, what's that? More plains? Maybe if I'll go there I won't fall asleep at the keyboard." Whereas skyrim, "I wonder if I can scale this fucking mountain by humping at it for an hour!"
Well, ok, that's not the best example, but I found myself doing a lot more of "for the hell of it" exploring in Skyrim, whereas Cyrodiil was more "Oh get on with it already." Never bothered to play it enough to even see Oblivion.