There are plenty of diverse landscapes that can be made for Skyrim to use as the setting for any major expansion. A dense lush forest (like the forests hat covered all of Scandinavia and Northern Europe a few hundred years ago), extended ice sheets covering sunken lands, and a vast underground chasm (think Morrowind's magma type caverns) comes to mind. There is also scope for the dragonborn to look skywards, learn to fly and start to raid cloud fortresses, jumping between them like a ninja paratrooper :facepalm: