this is like having a young bad ass dictator (like one of saddam's sons) fight a random old general of our army. of course the young guy wins.
Ulfric isn't exactly young. Remember, he served in the Great War 30 years prior...so, at bare minimum, he was probably 20 or so then. By the time of the civil war, he has to at least be 50.
The game doesn't do too great of job displaying age though. He
looks like he'd be 30 something. (According to her dossier, Delphine is in her 50s and she doesn't look it either.)
The Empire sided with the Thalmor, Shor is against the Thalmor, the Dragonborn is a manifestation [Shezzarine] of Shor. The Empire can never win.
I would love for nothing more than my main character to ride Odavhing down to Sumerset and take out as many of those damn high elves as possible. Go out in a blaze of shouting, dragon riding glory.