which one would you remodel and how?
Personally I'd change undercity. I'd have the goblins blow away all the ruins and such on the top and make the city more like a giant pit. In the middle of the pit is a tower with an opening in the middle with Terenas's grave and at the very top is his throne purched ominously at the top of the tower.
Then I would make the middle section wider and the roof a bit higher and I'd get rid of the middle ring with the auctioneers so that you can just fly straight from the middle to any of the corners.
So what city would you remodel and how?