There were two things I was unable to transmog: a polearm onto a 2h sword, axe or mace, and a fist weapon over a sword/axe/mace. It seems that the main hand/off hand restrictions are entirely gone as well, but I had a difficult time testing it for certain since I had no off-hand weapons in my collection at present. I tested a fist weapon and could not transmog it over an axe or sword or mace, which was a mild disappointment, but I'm still very excited over the changes.
At last, everything will be Ashkandi forever.
Mists of Pandaria is here! The level cap has been raised to 90, many players have returned to Azeroth, and pet battles are taking the world by storm. Keep an eye out for all of the latest news, and check out our comprehensive guide to Mists of Pandaria for everything you'll ever need to know.