We have to look at it from all sides, not just one. I am in no way defending Ulfric, merely defending the nords. Surely if a nord went to another place in tamriel besides skyrim, he would be persecuted just as other races are in skyrim. Nord opinions should matter in skyrim, because they honestly kind of own skyrim, just like the high elves own Summerset Isles and the imperials own Cyrodiil. It isn't right that the nords should have to follow the ban on the worshipping of Talos, because of the White-Gold Concordat. The imperials knew the nords held Talos sacred, but they did not hold him in such high regard, so banning the worship of Talos was an easy agreement for them to make, knowing damn well the nords would be pissed.
In that respect, Ulfric was not the man to do it. He is greedy for power and to me, he would be more of a tyrant masking as a great king. You should for all people in your land to make a great king, and this is something Ulfric would not do. He even abused the power of the voice, which is something that should not be used in the way Ulfric did it, the greybeards do not train you in the power of the voice just so you can kill others for your own political agenda.
I do not regret that I killed Ulfric Stormcloak, but I do regret not driving the empire out of skyrim.