First of all, this is in the wrong forum. We have sub-forums for a reason. Use them, please.

With that out of the way, there is ZERO reason for an AH. Not only would it simply duplicate the market ward functionality, it wouldn't even duplicate all of it since an AH system likely isn't going to be able to handle buy orders (where the retainer has gil allocated to buy certain things from players), and it definitely isn't going to be able to handle repair work orders. There are only a few rough parts of the current system left. Those who are STILL clamoring for an AH at this point are doing so simply because they don't want to use another system, rather than any actual valid reason.