We can't really judge that very well until we know what the game actually encompasses. But my guess would probably be a portion of high rock, or maybe morrowind.
maybe they'll lead to a dadreic plane like oblivion bliviongate: or they might do new lands like they did in Morrowind which is a nice touch it mainly depends on the story and how drunk Todd is after the game release party...........better hide the car keys
I was really hoping they'd go all out, do another separate area. Like Summerset Isle. Then we could get some of that "unearthly" element that was present in MW and the Shivering Isles expansion.