Its all about different perspectives. You see him as a megalomanic as someone who is just wanting power for the sake of power, whereas I see him as a man with a goal and to achieve his goals he needs to be the ruler. You see the empire as the sole salvation for the world against the thalmor porely on the sake of numbers, whereas I see it as without a total reform of the empire after all the mistakes and betrayals to save its ass to which smaller countrys united against a common enemy wouIld be able to do the same thing. I see a country that isnt tainted in its intel devision or military division by the thalmor having better chance at difeating an enemy than one that is infected in all areas of military and govt by the enemy to which theenemy would see preparations and how well the enemy is being orgainsed.
This empire isnt the tiber septim empire of the other tes series, I dont see why a new empire or countrys ruled of their own would have less than a chance than with an empire that just drops countrys or betrays the subjects they suppose to protect.
As far as windhelm, ulfric isnt in charge of the rebuilding of civilians who dont pay taxes or contribute to the money that is needed to use for the rebuilding when a war is going on.
Also its all about perspectives and realizing that charectors are not to be taken on face value, u have to look at them in different angles. Tulleus is a good man but also one who dosent think twice of capturing civilians for the thalmor or to use deceit to get what he needs.