This might be a dumb idea but, I have seen a lot of people asking to add backpacks , wings etc.
I understand the concern of the GM's that it might throw the balance, but what if such items would be added as costumes without any stats. In my experience a lot of players want to be unique in this game, which it not always presents so it would be a nice option .
And adding this options with options obtaining them such as : 1. quests
2. donation
3. in between player vending
It would add more stuff to do for players. Obviously it will add a lot of work for the GM's , but maybe it would be something to consider.