What character sees, player sees. Descriptions are just a bonus.
I have to disagree with this. Sight is just one of your senses, and one of only two you can give in a 'realistic' way, the other being sound. You can not touch something and tell what it feels like just at a glance. You can not smell the odors coming from it. Is it hot or cold? Does your character ever recognize an object he has looked at before? The answer to that last one is no.
When I go to the bookstore to see what new books there are, I do not look at each book individually. I glance over entire shelves quickly, allowing me to see -just- the books I have not seen before, while passing over the ones that were there last time. I could not even tell you -what- those old books were, just that they are not new. That is a trait that has developed in humans during our long past. I am not sure what the actual term is, but I like to call it the "what is new?" trait.
It is the same for many things. Go into you house, room, or any familiar place and glance around without looking for anything. You do not really -see- anything new, as your brain has recorded the info in that room so many times already that it just recycles old memories and splices them together after you leave, telling you that you haveone again been to your room.
Now, if there was a single new thing in your room, the story would be much different. Your eyes would be immediately drawn to it. Your brain would shift gears into high alert "what is that?" mode. You would not notice things that have been in the room for the last hundred times you have been in there, but -that thing- would jump out in your mind. It would be recorded as "the time I first saw -that thing- in my room".
Another example. Let's say we change just one word in your favorite movie. Not even a big change. Even if you did not notice exactly what it was, you would feel that -something- was not right.
Another example. Go into a place you have never been in before and look around for a while. Study it. Now exit and have someone change something. Going back in, you will be able to pick it out right quick.
Now, try doing that with a bookcase in a game with a repeating and limited texture.
Last example. This is one you can not do by simply adding new textures. If -nothing- is visually changed about a familiar place, but the smell or feel is not the same, you will also immediately pick up on it.
So, yes. I agree that things you have not seen before -should- be highlighted different than things you have. If you have been to the library before, new books -should- jump out at you (as they do in my real life anyways). If something has been moved, you character should notice, even if you do not.
When everything is new, you notice everything. When only a few things are new, you will notice those things first. And that, my friends, is simply the way it is.