Now before I present the I must admit I am relatively unfamiliar with how servers work and they way they serve up the zones in this game.
That being said, I propose that the market wards be the same in all towns, similar to how you warped into a interconnected zone for Choco racing in FFXI. They could eliminate the space they are using for two towns to increase capacity to make a single set of wards across the world. On Trabia the only place to find goods is in Uldah and I imagine there is a similar situation on other servers as it's centrally located between the 3 towns and makes for a natural gathering point. This also taxes the server in Uldah as I notice an immediate spike in lag the moment I waltz into town.
If my proposed plan is viable then I believe it would help to alleviate the clustering in that zone and also help players be able to find gear and items in every town without resulting in warping over to the main gathering town to be able to find anything.
Also in the event SE ever decides to cave into the pressure from that certain percentage who is bloodthirsty for an AH, they should definitely make it universal across all cities.