Alright, I'll try to explain myself a bit better here.
So let us take into consideration that the entirety of TAMRIEL has had its military forces depleted by quite a sum, however, the Thalmor still hold the upper hand since they have managed to maintain their Dominion over conquered lands and still play a huge role in Imperial politics. Let's also acknowledge that the Imperials are waiting for the right moment to strike a counter attack and that the Thalmor know it.
In the end a Second War in inevitable.
This is why Skyrim needs to be on the Imperial side.
The Stormcloaks naively believe that by defeating the 'oppressors' they'll retake their home and restore what was theirs. Ulfred might or might not believe this, but it doesn't take away the fact that what he's doing is selfish, spoilt and stupid.
In the scenario that the Stormcloaks win, the country will have been ravaged by the war, the military might severely depleted and the smallfolk sick to their balls of war. They've had ENOUGH, and with a entire province tired and lost in what I'd call that 'come of regret' the Thalmor, who haven't done anything but spectate, need only roll in and that'll be enough.
Ulfred is not a messiah, people don't think that way. They won't follow him to the ends of the earth simply out of charisma. This fight has been going on for quite a while and NOTHING has happened. Hell, it takes a 'special dude' to actually do anything. The lords he has placed in their old nobility's stead are most probably there for the profit, nothing more. In the end, relying on the nobles isn't reliable at all. A man's word is worth nothing in the face of an immediate threat.
What fight are they going to give the Thalmor if they've JUST finished the last one. You'd be a fool to think that a breather is going to be given. And what can be done?
Nothing at all.
Hammerfell are probably doing a lot better than the Nords because at least they have a common purpose. They didn't have to slaughter each other to decide who gets to wear the silly hat.
Now, let's consider that the Imperial win.
The same thing happens.
But.
The Treaty AND the backup of the rest of the Empire gives them that better chance to actually SURVIVE! Remember, the Stormcloaks are a recent military organisation. The Legion has TONS of veterns and TONS of experience to go with it. Also, if they win, the Lords under Ulfric will simply be replaced by other loyal retainers. I bet there are lots of nobles wanting a position ANYWHERE just to climb the social ladder.
So in the end, the Imperials have the man power, the nobility and the resources. The only reason they haven't pushed HARD on Skyrim yet is because the Thalmor are waiting to stick their 12 inch penis up any hole they see fit.
It's simple.
A house divided will fall. It applies here. And any thought experiment that does NOT involve the Dovahkiin kamehamehamin his way to lololol land results in an obvious lost to the Stormcloaks because in the end, IDEALISM does only so much when you lack men, resources, power and the support of the Nobles when things go to the dump.
And no, recruiting 'the people' is not an option.
I don't care about INGAME things, no one born in a village knows how to swing an axe because his racial bonus gives him a plus 10 to two-handed weaponry.
Don't make me post Septon Meribald's monologue just to explain to you the basics of perspective. Just because you look scary in that chainmail does not mean you're a badass.