Like other have said, they didn't say we wouldn't get some changes, just nothing like the overhauls we are getting for the outside zones. I mean the old zones are more or less getting changes from the ground up with new elements and in some cases completely changed structure (North Black Shroud becoming a normal forest with some open fields instead of the labyrinth it is now). We already know new structures are coming to some of the cities due to the art work (The Floating Coloseum on the outskirts of Limsa being one of them). My guess is they will tweak some of the layouts of the city to accommodate new content and new dynamics but the general look of the city will remain fairly unchanged. For instance they could open up parts of Gridania by demolishing some terrain, add new buildings and make it possible to go inside pre-existing buildings, but that doesn't mean they destroy the city and build a new one like they more or less are for the out door areas.