I'd like to give some examples as to why the things the OP are asking for are good things. Note that I'm not saying or intending to imply that the herd instinct that moves most of the populace into one city is a bad thing. However, I will say that ignoring that drive should not result in the loss of ability to interact with our peers as it does currently. Anyway, on to the examples. . .

Say I'm sitting in Gridania, slowly crafting my way to 40 CRP. Meanwhile, there's a grind party forming over in Uldah that's sitting at 7/8, just waiting on one last person to show interest before they head out. Now, I'm not *actively* interested in a grind party, so this isn't even a situation in which better party search features would help (or it wouldn't help me, rather). However, maybe if I saw that a party was about to head out, I might decide to break up the monotony of crafting with a little running around killing things. As it stands now, though, there's no way for that group to get their message out to any other cities. In fact, they really can't even reach all of Uldah unless they spread out throughout the city and all /sh (wanna talk about spam?).

Alternately, let's say there's someone using /sh in Uldah to try to sell a Buccaneer's Shirt for, oh, whatever they go for nowadays. Unfortunately, the only person on with the money and desire to buy it is in Limsa at the moment, with no intention of going back to Uldah any time soon. How are the two of them supposed to meet?

As far as the MW, Wolfie and I (and others) have argued that one to the point that I'm not sure there's any carcass left. If you really wanna see my thoughts on it, I'm sure I've posted in most of the MW vs AH debates; feel free to read them.

As to the SW/Org comment someone made, I'm not saying that people won't naturally centralize. From what I can tell, neither is the OP. However, even in your WoW example, there were people that chose not to congregate for whatever reason. That cost them nothing in the way of gameplay opportunities, though. Most parties were formed in Trade chat, which was linked among all the cities; and most day-to-day buying and selling was done through the linked AH. Heck, you could be in Exodar, which was almost always devoid of players, and you'd still be able to interact with everyone in Stormwind, or in Shattrath, or in Dalaran, or Ironforge, or Darnassus. Or at least, you could interact with everyone that was in Trade chat.

Anyway, again, not saying that herding to one area is harmful or bad, as such. Just saying that those of us who'd rather not be in Uldah not be left out in the cold. The good news is that they've already said they're looking into adding a wider chat option that will allow cross-zone communication. So, really the only thing left to ask for from this thread is a centralized economy. . .