The latest UESP digging has revealed new music, new locations including Evergloam and Artaeum, the sload mobs, new loading screens (including one for Mephala’s Realm), quests revolving around the Mages Guild and Psijic Order, and the jewelry crafting skill.
Still grumpy over the focus on Summerset and High Elves? Our own ESO columnist Larry Everett recently penned a piece examining some other possible locations for future DLC. Also, Justin is right there with you.