adding something like cosmetic slots would be nice you don't benefit from gildings but you could put any gear you want in the slots for appearance but they don't give you any defensive or attribute benefits at all whatsoever
you can even have it locked behind subscription so I don't care it's a thing I would be willing to pay for
more cosmetic choices would be great in general overall for character appearance besides hats
there's a couple of hats I wish I could buy but they're no longer available which also kind of sucks I could understand you want to make some of them special but some of them should be brought back every once in awhile like once every two to three years