They fixed a LOT of bugs. And not just in new content, they went through ALL content.
Also, a new monthly event that's a lead-in to the expansion. The fair is parking in front of one major city each month for a week. Simple quests resulting in tokens to spend on appearance armor and house items. Some really nice stuff, too. And in each city, there will be a collection quest.
Link to the LONG list of bug fixes.
Link to the city fair info.