When the game first came out I really wanted a AH (like FFXI). But now that the wards are a little more stable and have some search functions, I am leaning towards the wards more now.
Likes:
1) Retainers can stay up selling your items and not return them to you after a few days because nothing sold. Again this varies with up time in the wards, but I have had retainers on as long as two weeks with no crashes.
2) You can model your wares on retainers. I have seen some neat looking gear for sale that I may have ignored until I some a retainer similar to my character wearing it.
3) With multiple retainers you can focus on the types of items being sold or have up for repairs.
Dislikes:
1) The ward crashes. Granted it has been less lately.
2) The search feature. It's not complete and I know that. SE has plans for improvement and I am patiently waiting for them.
3) The tax on certain floors for selling specific items. The floors should all be the same tax rate until we can get more retainers. but most of us i think sell a variety of items at once, not just one kind.
Would like to see:
1) A global search of all cities. But limit purchase to just the city you are in. Another idea is you can pay a "delivery fee" to purchase from a city you are not currently in.
2) Use of the Silver & Golden Bazaars as an actual AH of some sorts. This may be used for either placing or purchasing special type items only. Not the everyday items we find in the wards. Maybe Beastmen type currency would be used instead of gil. All these new coins we find on special leves but have no use for yet.
3) Sold item alert sent to chat log or a message / mailbox.
4) An increase in the amount of items to sell, preferably the same limit as you can carry (like in FFXI).
5) No slot penalty for reward when placing and item in Bazaar or Retainer for repair. At this time we are limited to only 5 repairs and unless you have all your crafts high enough to fix all your gears, this can be unnecessarily restrictive.
So personally, I don't think we have to push for a AH like FFXI had, instead some modifications to the wards and other ideas will make it more unique.