i hate how i make a cool tmog on one of my classes and 1 specific item is class locked so i cant ever use that tmog on any other character just because the gloves are for demon hunter… leather already has bad enough, limited transmog options but thats just salt on the wound.
also why is it we cant tmog specific class items but i can tmog the entier warriors tier3 nax set on my paladin???
Because for now, as implemented, transmog limitations follow use limitation for items with class-specific restrictions.
There is no other why, than “that’s what the developers decided.”
I think these might lift in the next expansion.
yeah watched the Q&A and ion out right said that we can unlock mogs on a class that cant use the item with warbands but not class specific items even if you have that class in your warband and i went ???
their design philosophy is just really unfun at times 
i really wish wed be able to use all armor types no matter what class we are and have no class set restrictions but thats never going to happen
edit: also if we could tmog a 1handed weapon into a 2handed sword even if we cant use swords because your transmog being restricted by class feels bad and it doesn’t let the player create their own version of a character. like the devs said before a priest in plate armor looking like anduin would be badass but the balance is an issue. so why not just let priests mog into plate and 2handed swords to look like a ret paladin while still being a priest??