Could try a complete overhaul with it and make it into a raid/instance...Kingdom quest. Wouldn't even mind it being turned into a quest driven event, atleast it will add some change to the same old things we have been doing.
No just...no. There's no real disadvantage of having those stated items. It will only make it harder for new members to catch up to the rest when you removed those def/dmg. I thought you wanted more people to join not push them away. Just let those pieces alone and maybe think about adding alittle more costumes with dmg on it ior non at all. It won't screw up the economy nor make it any less balanced.