I don't think the Stormcloak or the Imperial ending should be canon, but I am going for more of an Imperial ending. I like the Nords, I think they are the best human race, but I don't like Ulfric or his Stormcloak Rebellion. Ulfric may be fighting the war for the rigth reasons, but he only wants power and he is willing to step on anyone who gets in his way or he considers "weak" or "not a true Nord". Where I come from, we have a word for people like that.
Ulfric wouldn't bring back the old nord way, he would try, but what he would do it bring about the Red Year-like event for Skyrim. With the Empire wanting to reclaim Skyrim. The Forsworn still being an issue, and the threat of the Thalmor, this may bing about the Sundering of Skyrim. The Empire we all know is dead, as is Ulfric's ture nord way. Compromise is what he lacks. I reccomend that they handle it like this:
The war rages on for a few years after Skyrim. If Ulfric dies, he is considered a martyr and Tullius is killed in battle. If Tullius dies, the war continues and Ulfric is killed in battle. The one constant there is that Elisif survives, as does the Dragonborn. The Dragonborn s remembered as a commander during the Season Unending and plays a crucial part in ending the war. After the Mede Emperor is killed, a power vacuum emerges in Cyrodiil, resulting in infighting. A peace treaty, allowing the worship of Talos is singed in Skyrim by one of the factions fightng for control of the Empire. The Nords take over that faction and now control Skyrim and most of Cyrodiil, some under the control of the Thalmor. Also, the Dragonborn dissapears during the war and is persumed dead by many, while others still belive he/she is still alive.
There. Skyrim is free from Imperial rule, since it's the other way around, a Nordic Empire of Skyrim rules Cyrodiil and Skyrim, as well as part of High Rock and is allied with Morrowind. Elisif would have a bastard son, for now, dubbed "Torygg the Younger" who is a student of the Way of the Voice. Ulfric is dead, but no one knowns who killed him. Perhaps the Dragonborn, perhaps the Thalmor.
Otherwise, perpetual war is also a worse ending. Stormcloak canon ending basically screws over everyone, including the Nords in the end. Imperial victory is the good guy ending. I'm sugesting a medium, with Elisif as High Queen, a young woman with a strong heart, who cares deepy for her people, and will one day become a strong leader. She's the only constant.
Don't get me wrong, I like the Nords, they are my favourite race, along with the Dunmer. But I hate Ulfric and I admire Elisif and Balgruuf. They care more for their people than Ulfric and his supporters, who care more for tradition, religion and themselves. Sure, the Jarls were baught off, but hey, nobody's perfect, right. Ulfric is a coward as well, a traitor, a murdered and a biggot and a racist. Hells, I would rather have Erikur on the throne than Ulfric. To me, Elisif will always be the canon leader of Skyrim, just because she doesn't die during the questline.