It's likely that Skyrim will fall apart after the civil war- if Ulfric wins, his death means that the Jarls start fighting amongst each other for control, turning SKyrim into a patchwork of city-states. If the imperials win... well, they can't keep Skyrim and the Holds turn into semi-independent city-states.
At least, that's how I think gamesas will define it, or in a similar way. It might make a mention of who won, but the victory will be short-lived, and the outcome would be plausable from both sides.
but almost, if not all cities in Tamriel are city-states bound to a high king/queen and then the Emperor if it's on the empire, also the Jarls have no need to fight among themselves for the throne because the Moot was created (LONG before the Stormcloak rebellion) to prevent exactly this situation, when a high king/queen dies, the moot gathers and who receive more votes is aproved as the new high king/queen, the Stormcloak rebellion will not change a thing in this, it's not their goal

(and the rebellion only started because the Empire flaged Ulfric as a murderer and traitor because of a duel and prevented this way the moot to gather, otherwize after the death of High King Torygg, the moot would gather and a new high king choosen)