I think my favorite new feature might actually end up being polishing. The fact that you can use custom designs on them is really cool. I can make it look like fall leaves are falling inside my house or make little ghosties and bats floating around inside. So great.
When I was messing with them in Paradise Planning, I was able to undo them by reapplying a wallpaper to the entire room. I feel like it should be the same case in your own homes. I haven't actually tried them in my own homes yet, though.