It doesn't have to be the next incarnation of the Dragonborn to drive out the Thalmor and their Dominion. The Dragonborn himself is hardly wasting away of old age after defeating Alduin. The last expansion for TES:V should take place during the war to free the rest of Tamriel from the Aldmeri. However, I do not believe that the Empire should stay intact through this crisis. Skyrim and every other "province" that was held by the Empire should either secede or be granted independence. After this, those regions whose common interest is to oppose the Thalmor and their Dominion should ally with each other and fight them off. Tamriel should be composed of an alliance of equals instead of an Empire and its subordinates. That is the only way lasting peace, I mean truly lasting peace, can be achieved. In my opinion, the provinces that are free of the Thalmor have very strong advantages. The Aldmeri have annexed Valenwood and subdued Eleswyr. So, in addition to the Altmer, the Dominion also included the Wood Elves and the Khajit, who, I don't suspect, are too eager to fight for their elven overlords. The other regions of Tamriel, which I presume to constitute the opposing side, have the Imperials, Nords, Bretons, Orcs, Redguards, Dunmer, and the Argonians. Actually, I don't remember if Black Marsh is a part of the Admeri Dominion yet, but anyways: The Nords, Orcs, and Redguards are excellent fighters, the Bretons and Dunmer are good mages, as far as I know, the Argonians are supposed to be good spies and such, and the Imperials are supposed to be a sort of factotum race. If each of these races can find the will to fight the Aldmeri Dominion, I am certain that they will be able to defeat them. I do, however, think that this will not be possible until all the races are sovereign over their respective territories nor until they unite to fight the Thalmor off.
