Do all inns look the same? Have they really just copied anod pasted?

Only the non-city ones.

The Whiterun and Markarth are different I think, maybe all the main ones are unique, the rest are just copy/paste though.

Well Markarth and Whiterun are different, but the smaller cities and the ones out in no man's land, yes, yes they are. But that precious time had to be devoted more to detailing the fish and butterflies you can catch. Sacrifices must be made.

yeh so the same models were used in serveral different cities in Morrowind, most of Skyrim's and Oblivion's building are only used once