Well, technically we will have dragon blood in our veins, just like the Septims did, so maybe we could revive the failing empire and re-light the dragon fires. We won't be going to Cyrodiil though, so the most we could hope for as far as being on the Imperial side for the civil war is to rally all the imperials in Skyrim. Or conquer all the Imperials and watch their crumbling empire burn
Personally, I want the game to end with me sitting on a throne of skulls, king of Skyrim. One of my men will as me:
"Dovahkiin, what is good in life" to which I'll reply:
"To crush your enemies, see them driven before you, and to hear the lamentation of the women".