An AH system actually has some negative aspects in such a complex economy.

With the interdependence of crafters in the game, the retainer system allows people to leave items on their retainer without having to constantly repost them, or manage an insane log of auctions.

One problem with an auction house system is that many of the items will simply never be posted, similar to how in other games you see plenty of low level items, no mid range items, and then level cap items on AH's.

A better solution than an AH is to increase the number of items retainers can post to 1,000, give each player 4 or 5 total retainers (because crafters need retainers for all sorts of wards), and add a text search feature to the item search.

It would also be nice to clean up the wards to make them more organized, and to remove the price search feature, since too many items are greatly undervalued in the current game due to gil wars, or players offloading items onto the market.