Is the Karazhan Chess encounter tunes correctly? From doing this on retail in TBC, I always remember it being a snooze, but here, even with a full 10 people it can be difficult and feels like you need a little luck.
I think it's because TBC bosses are somewhat buffed, and when your in a "vehicle" fight, which dosen't scale on your level or gear, its going to be much harder.
I stopped even try karazhan since no raids Iv'e been in (except one with very good people and discord) ever cleared the chess event.