BIGGER CITIES!! MORE PEOPLE IN THEM!! MORE THINGS TO DO!!
The cities in Oblivion felt way to small, sure it was nice walking around in them but they were more like small towns or suburbs to IC then cities of their own.. at least that is what I think..
The bigger the giant.. the harder they hit the ground when I slay them..
Honestly I hope the giants in Skyrim will be AT LEAST as big as the Gatekeeper on Shivering Isles.
Some, like Chorrol, were definitely very sparse, but cities like Skingrad were very densely packed. Medieval cities wouldn't have been that dense all the time would they? We know from art that Riften will not be that dense in some parts.
Actually medieval cities were usually very densely pack with people in consideration to their size, mostly because the city walls prevented them from expanding to much and there where no things like skyscraqers back then.. (not counting castles or churches..) and the streets in a typical medieval city would be about the size of the streets of Skingrad.. and smaller..