It's true that they couldn't leave Catherine Palace as is, since it was nothing but ruins when they got through with it. So there had to be restoration of course. I am talking more about places like the AP, where most of the original structure is intact, and I would hate to see it "restored, i.e. things changed and added, and become "touristy" like some other palaces, and lose it's authenticity. Not to say that it shouldn't be upkept, like the roof, the basic structure, etc., but "restored" in the sense that they have done with some other places, to a point where it loses it's original flavor - I am not so sure about that.
Last week I had a similar conversation with a curator at the Edgar Allan Poe House-Museum in Philadelphia. Right now the house is as bare as can be: basically the original structure and walls and that's it. The museum is thinking of "restoring" it, bringing in furniture, etc. The problem is, they don't really know what kind of furniture was there, where it was located, what the place really looked like... Right now, when you walk in there, you can really use your imagination and feel the former occupants, and they feel real, it feels authentic. But if they do restore it - I think it will lose that, and become just another museum...
For those interested in EAP:
http://www.dlackey.org/weblog/images/PoePhil.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/d/db/RavenStatue-Philadelphia.JPG/300px-RavenStatue-Philadelphia.JPG