The auction house UI is clunky, over-generalized, over-simplified, and can operate incredbily slowly.

Ways to improve it:
1) provide more categories for items.  A person looking for level 7 bracers shouldn't have to scroll through page after page after page of every other kind of jewelry (!) for every other kind of level  to find them.  (!) because lumping bracers with jewelry suggests the developers don't know what bracers really are.  (Hint: they're not bracelets!)  But setting aside that point, an auction house really is just a database, and modern databases don't lose functionality when they feature more categories, so it shouldn't be that difficult to give us subcategories (e.g., "rings", "cloaks", "boots") within subjects such as "clothing" or "jewelry".

2) Give us a search feature!

3) Give us transaction history!

4) Commit more server resources to its operation!  At times we might have to click the forward/back buttons dozens of times before the server will recognize the input.

5) Give us maximum amounts we want to bid, so that we don't have to deal with this clunky, slow interface constantly in order to make sure we win the item we want.

6) Give us precision in time limits!  Being told there's "1 hour" left in an auction which really has only 7 minutes is remarkably frustrating, and leads to situations in which only the most obsessive win items, because they have to sit at the auction constantly to make sure no one overbids them--and then rushing back to place new bids because they're not sure how much time is left when someone does outbid them.

Overall, Turbine's implementation of the auction house is precisely identical to how it's coded most of the game--simply sticking something in with generic functionality and never improving it afterward.  If you want to figure out why DDO hasn't sold the way it should have, this is a perfect example.  There was an infamous Ken Troop posting back in testing in which, essentially, he said that if gamers didn't like to play the way he did, too bad.  Though that attitude at last has begun to change--the game now features more flexibility in char advancement, for instance--the auction house still demonstrates that Turbine can be ridiculously slow in figuring out what gamers want and how to provide it.