Many other games have a minimum list price and a buy now price. People can bid on the item until the auction ends or choose to buy now. I would totally like to see this. That way you don't post an item and someone undercuts it by 1 gold a few mins later.

The filtering system could use a rehash as well. We should be able to search for all mythic items, etc. from every category under one filter. As it stands you only see the items for the specific category of item you have selected. Instead of the categories being displayed separately it could all be under one category and you can check off the boxes you wish to search from. Item type is one category, class type another, rarity, level(type in range) and bid price(type in price).