I think there are several advantages to FFXIV's Market Wards compared to FFXI's Auction House.

1.) Can sell 10 items instead of 7.
2.) Don't forget that there's durability in this game and I think Market Wards coincides with that better than an AH.
3.) Can not only sell things, but can also seek/buy things with your retainer when logged off, FFXI couldn't do that.
4.) Could add content into the Market Wards/Retainer system to make things more fun. Such as quest, leveling up, etc.