It would be nice to be able to filter the Wanted items to exclude items with an Asking Price of 0. It seems to me that some people are using this feature as a personal list of items they'd like to have, and not just items they're looking to buy from someone (many are EX). I'm pretty sure Wanted is intended to be the opposite of the Bazaar.
I'd like to point out that you can use the Item Sets feature to make a list of your wanted items, which you can set to private if you want.