I think the fact that the actors couldn't touch the walls in most of the locations they were in adds to the sterility.
I think the mini sets are pretty cool, and if you have the "Creating the Worlds of Star Wars 365 Days" book, you may see that a lot more of thre prequels were shot against mini sets than you might have guessed. But, as was just said earlier, they should have been used for extensions and had more practical sets for the actors to act against.