Ok got a few ideas off the top of my head.
First has been said a done window on the merchant window but a done button on guild bank would be nice as well.
Second on the bazaar search could you add a thing to search by diety. This would help those looking for cultural for thier character.
Third on the barter window could you put a way to search by a specific buyer like the barter wondow has.
These all seem like good ideas that would help all.
Nylana