So I understand why they don't want to allow us to trade between players.
What about having a Guild Auction House? The prices could bet set as normal. But maybe some of the profits could go to the guild. That way when I do dungeon runs and only get items for classes I don't play I could give my guildmates a chance to buy those items first. Or when one of my guildies makes 50K repair hammers while grinding his armorsmithing I could buy some from him. Stuff like this strengthens the game's sense of community. And that keeps people playing longer.