Here's my argument (spoilers unintended yet unavoidable, so be warned):

First: antagonist
The Thalmor are an unjoinable faction. While it's true there are many unjoinable factions in Skyrim, factions of the caliber of the Thalmor are generally joinable. Not only are you not allowed to join them, the main quest, the College, and the Skaal force you to take sides against them. In fact, their enemies (the Psijic Order) are painted in a positive light. We have essentially been given an enemy that we currently have no ability to conquer. Is there another Elder Scrolls game that gives such a strong enemy that you can't thwart?

Second: protagonist
Obviously, the expansion is going to have you beat the Thalmor. With their defeat, what would be gained? Basically, you would be *mostly* reclaiming the land that the Septim Dynasty had united. So since you've beaten the elven oppressors, who gets to rule this newly-conquered area?

You do. YOU are the Dragonborn, just like every other emperor of Skyrim has ever been. Are there any other emperors around? Nope. Definitely none that are Dragonborn. It's also incredibly convenient that a quest in another faction leads to the death of the current emperor. As the new council in Cyrodiil deliberates, who will stand out as emperor material? Certainly Alduin's Bane is a contender? And a Dragonborn, so potentially related to one of the various dynasties?

Possible shortcomings of this speculation (which don't completely destroy the argument)

*If the empire is defeated in the rebellion, the Stormcloaks will still need to deal with the Thalmor. When they prove successful (led by Ulfric and the Dragonborn), they will essentially have gained half of the former empire and will be in a position to reform it. Siding against the empire in Skyrim could possibly lead to its reformation.

*Obviously, a storyline of this magnitude would have to be an expansion and not DLC (and a large one at that).

*The fact that the Dragonborn could be any race might mean that he or she is a short-lived emperor with no heirs. There would have to be a book describing these events in future games, and they couldn't leave something this important to the "unknown hero" or unisix tag.

Thanks for reading. I don't post a lot, so any criticism of any kind is very much appreciated.

No. I didn't even read it.

Enough with these "Become Emperor, Jarl, Own Land" bullcrap.