closed cities (if they must have cities in child worldspaces then please don't use the same boring, bland, giant city walls that they used on every city in Oblivion)
Having the cities be open would be truly fantastic, but I'm not betting on it... At least not before the modding community gets their hands on it. But even if the way they seperated city cells just alternated between stone and wooden palisades, it would be a lovely change. More variety than that would be too good to be true.