I agree with more compact but detailed being better. I normally love exploring huge areas, but they did an excellent job with TW2, making the environments beautifully detailed and fun to explore. And it just seems like the way to go in an urban environment. It's weird having such a dense city with nothing to do, no buildings to enter. For once I'd like to be able to go into a lot of the buildings I see, without loading in-between, and not see the same interior over and over again. That would be my ultimate open world city.
On a side note, I hope they do go kinda crazy with the height. I wouldn't mind them making it as big as possible vertically, because it's not like you're going to explore the roof and sides of every building in the city anyway, and there isn't really supposed to be anything up there in the first place.
