I played a large amount Wizard 101, which was recently updated with the Grizzleheim update. Not only is there a new region, which branches the usual leveling path, but there are a whole slew of core mechanics that were just added.
The first, and in my opinion biggest, core improvement is the Bazaar. The Bazaar acts as a trader depot where the NPC will buy just about every item (some have the “No Auction” tag) for gold, and if it has an item in stock it will sell it back. Guild Wars uses this type of NPC-controlled market for materials, for an example of another MMO that uses this mechanic. It is a great system, and much needed in a game where items could not be traded in any way between players on separate accounts.
There are two issues. The issue that I am still on the fence with is in regards to the economic model used to determine buy price and sell price. The system is built so that the NPC gets a huge turnaround profit so as to get rid of gold stockpiles, but that is not the thing that concerns me. The Bazaar window has a numerical counter that shows how many of a particular item are in stock. This counter caps at 100, and I am not sure what that means. Will price be more severely affected as things are sold when the Bazaar already has 100 of them in stock? Or, is it merely a faux consumer gauge? The counter ending at 100 items in stock seems awfully low in a game where there are over 1,000,000 registered users.