I really wish we could at least be able to trade these poly-morphs because my level 90 ice character has 2 pages of them and I don't use them on that account.
I'm not sure if any vendors outside the Bazaar will but TCs, but if you need to free up TC space, right-clicking a TC allows you to destroy it (you'll get a prompt "Are you sure you want to destroy the _______ Treasure Card?")
Yeah KI seems to have gone overboard with polymorphs, first PVP fiasco and no use in PVP, no auction, no trade, etc. At this point beyond a crafting reagent they don't really have a use IMO. I never see anyone use in battle except for those to whom they are new. And the few friends that I had that trained polymorph quickly reset their training points. They caused a good deal of excitement when released but with the debacle that followed and heavy handed restrictions they are now useless and worthless since they can't be sold at all and must be used or destroyed to get rid of them.