Trying to decorate using Abyssalcraft stairs, when they're right-side-up, they seem fine, but when inverted, they don't connect to each other well. Just to show you what I'm talking about, I made a very short imgur album: http://imgur.com/a/01Nse

It appears just about all of the upside-down stair rotations were inverted in 1.9, and I haven't noticed that (sine the normal ones didn't change, just the corners).