As I've said before, Ulfric isn't responsible for the downfall of the Imperial Alliance between the nations. Titus Mede II is. Mede II's incompetence knows no bounds. He's forever scarred the reputation of the Empire and this will hurt them in the long run.
The poor man was in Bad shoes

He inherited A weakened empire, Was attacked by the Thalmor. Lost Most of his forces, Despite winning one of the most brilliant victories in imperial history, He was still labeled a coward, Did something for the good of his people, only for his very friends to turn on him

Having a trooper who swore an oath to him, turn into a rebel leader directed at kicking him out, And despite all this he still showed no fear when death knocked on his door.