something troubles me.

[Unearthlybrutal]

I agree with you. I've played through amnesia 2 times.
First one was amazing, because of that I had no clue of what was to come.
Second time, I tried to empathize. I played it like I would be part of the game.
I imagined myself running in that Castle Brennenburg.

People have gotten sick of the same monsters, same furniture, same walls, everything.

That is problem indeed. Luckily there is still some good modelers who can make entities, furniture, walls, monsters, etc.. what fits perfectly in the amnesia's world. In my mod, I've tried to make a few new walls, but its quite hard (more or less) to make them look like that they are always been in amnesia.