Apparently the books weren't selling as well as Tor expected, so they changed the cover style so that it might be more appealing to the tasteless masses. The shift over to this new clichéd style is the reason why I didn't bother to pick up the hardcover on release, as I had done with the previous two.

They also changed the art for the mass market copy of Canticle.

The worst part of this is that I can understand the change, even if I loathe it. I know someone who ranted about the original art style and how it belongs in a museum and not on a fantasy novel. He also disliked the book because he didn't understand the setting... a real shocker, that.