This looks pretty awesome indeed. I would agree with not making things too glossy.
Also make sure that individual stones of walls are not too embossed; this kind of thing looks fine straight on from a distance, but looks increasingly bizarre as you get closer with a more oblique angle: the stones look like they should fall out of the wall. Its very dodgy if you look at the right wall on the second image closely (in Winnowing Hall), those bricks shouldn't be able to bear the load of the wall since they jut out too much.
Although less noticable, the same warning applies to floor tiles. A floor is useless if it looks like you should be tripping over and stubbing your toe on it every five seconds. I mean, would you want an uneven floor in your kitchen?
If you've been to a medieval castle or dungeon that still has the original floors (I have been to lots and even worked in one, I'm British and there's quite a few here, lol), you'll see that the floors are usually very worn down. Hell, you can see it in pedestrianised modern areas after 3-5 years of people being there. Such floors SHOULD NOT be sticking out at all, and will only be glossy due to damp or rain.
