Well, personally I've seen far more comments on Elsweyr than the other provinces.
(I exclude Hammerfell, Morrowind and Cyrodiil as they've already been done.)
And I doubt it will take place on Summerset Isles as that's right in the heart of the Dominion, and while I am not completely sure on it's size isn't the landmass pretty small for an entire game? (Seems more like an expansion area.)
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As for Falmer's blindness, they seem to be fine with their other senses, eyesight doesn't seem like it's needed for them, would help, but it's not a necessity.
First on all, they could scale it so that Alinor (Summerset) could be a game. And nothing says that we can't have both Summerset and Valenwood, seeing how both of them are part of the Dominion.
I believe the next game to be about casting the Thalmor down from the inside.
Eventually, there will be a game featuring the Akaviri (not Akavirians, Akaviri) and an invading force from Akavir.
My guess is that there will in total be 8-9 TES games.
As for TES V DLC my guess lies with the mystery of the Dwemer revealed (not with them returning) and something in Atmora the Cold.