Speaking of the next game, I wonder where it will be central to. Elsweyr?
Well, so far they have done Morrowind (Dark Elves+Argonians), Cyrodiil (Imperials) and Skyrim (Nords)...my guess is actually either Elsweyr (Khajiits+Thalmor) or one of the Elven provinces. I am almost certain not Summerset Isles, that would move the story to quick...but never know I guess. Maybe as a DLC.
I don't think they'd do Hammerfell quite yet. And it doesn't seem to be the most popular of places. But, there is backstory there with them winning against the Thalmor. Likewise, a lot going on in Elsweyr and a lot more than Hammerfell.
Plus Elsweyr should be a lot more pretty than Hammerfell would be. That would get a lot more attention at E3 than Hammerfell would...cause...LOOK AT THE GRAPHICS.
And I doubt they want to do another "human" province. So, it is likely to be something else.
And on top of that...if they do Elsweyr...they can do a Summerset Isle dlc...can't do that in hammerfell.
There is other provinces of course, but those two are more likely with Elsweyr being much more likely.
However Elsweyr is pretty small on the map (they can always LOLCON it and make it big)...would make sense to add Valenwood on top of it.
Fallout 4 will be out first though.