hmmm.... even if it wasnt unique, you couldnt transmog it to your offhand anyway.
https://www.wowhead.com/wotlk/item=5...agony#comments
But I think I get what youre saying. I think maybe what you mean is that it should be modified to say "unique-equipped" so that if you have one equipped, you can still loot one that you can turn into essence or loot it for disenchant or heck even sell it for gold if there is no enchanter in the raid.
I fully endorse this idea to change the "unique" --> to "unique-equipped" as it doesnt harm anything and there are alot of items like this already.
+1