Skyrim looks (concept art-wise) to pretty much blow its predecessor out of the water. Those drawings present some really unique-looking locations and I love that they're taking the very real process of ancient cities being occupied by different people over the centuries and applying it to their games. Why wouldn't a fully fortified and pre-built Dwemer city be reused by the next culture to discover it?
That is basically why I keep telling everyone that the picture we saw in the magazine, that everyone keeps calling a ruin, is actually one of the cities. It just looks too big to me and I believe I see an NPC in it. Oh well, 10 months and we'll know for sure.