I love the current fashion Accessory system we have now. It can be an umbrella, a backpack! That's just genius!
My suggestion here is a new kind of accessory:
Scabbards!
Samurai already came with scabbards, paladins, dark knights and vipers (swordman mains like myself) would love to have scabbards as well!
I understand adding to the already existing weapons would be too hard, so scabbards being a fashion Accessory would be cool