First, the market is great. Except that once you offer up your offer, it's up there for the world to see. Kind of like a giant world wide billboard, and someone comes along and takes you up on your offer. It can be anyone. Literally. From the guy next door, to the guy in the 1000,1000 corner who's 2000 squares away from you.
1) I would love to see a system that included the ability to limit either by distance or travel time.
2) It would be beneficial to have a system that would exclude certain alliances or players. Say, three total. Alternatively, limiting it to your alliance and/or alliance allies.
3) In the interest of making prestige a desirable thing to a trader, perhaps more exacting standards (5 instead of 3?)
4) A limited time non~automatic trade system would be awesome. Say, the person has to wait 2 hours, and during that 2 hours, the offerer would have the option to accept or decline. This could be turned off, or perhaps only bought with prestige.