I have become convinced that this will be the first major DLC, by choosing a side you stacked the deck, filling up the Holds with Jarls that support either Ulfric of Elisif. However, I think when the DLC drops we will be offered a 3rd option, becoming High King/Queen ourselves.
I mean we are the Dragonborn, and what have the Dragonborn done for thousands of years? Ruled the Empire.
Skyrim, I think, is about history repeating itself, the first dragonborn fighting Alduin, then going out and creating an Empire. Now we have to fulfill that function and create a new Empire. It will be like Shivering Isles but with the whole of Skyrim.