@Val the Moofia Boss He committed an act of treason, that rightfully gets you executed. It is not heroic to save someone rightly condemned to death. So let me correct you, you get a villain moment, because letting a condemned criminal escape his rightful punishment is what a villain did. He let them man who murdered his sovereign go, he deserves execution.
And no, there isn't going to be an alliance against the Thalmor. With the loss of Skyrim the Empire is going to be even weaker and lose what little holdings it has left. Then everyone can be picked off piecemeal by the Thalmor. With the recent war, the Empire will be hostile to Skyrim, and will want nothing to do with it. And the thing is, your statements on the Empire shows that you know nothing about the lore. There have been multiple empires and it has come back from worse. The Septim Empire was about to make a come back from being crippled by intentional mismanagement by a usurper, internal war, various shenanigans by their cronies of the usurper, and only collapsed to be succeeded by the Mede Empire by an invasion from Hell. If your metaphor holds, then the Stormcloaks are pretty much the supposed allies that helped destroy the Byzantine Empire, because they had a good chance of coming back until they were knifed in the back by the Venetians.
And Skyrim is ruled by the locals under the Empire. That is how they traditionally do things And on the same issue, what about Ulfric's actions in the Reach? Don't the locals deserve to rule themselves? Because by all accounts the Reachmen were plenty urbane when they seized power, only devolving into madmen after they got brutally suppressed.
If you look at how they do things in the lore, it is pretty much implied that the locals rule themselves as vassals to the empire and an Imperial Administrator runs the local imperial administration. So you get to rule yourself and get the benefits of being part of the empire. While with the stormcloaks, you lose your benefits- good luck on not being tarrifed to hell by the empire and paying exorbitant taxes on imports.
And Ulfric doesn't care for his men at all. Tullius does, he might be gruff, but he actually grows to appreciate Skyrim-which you conveniently leave out. Torygg who has no reason to lie, outright tells us the true nature of the man. Though, his actions towards Balgruuf should be evidence enough.
The Empire is the best bet, because it always has been the best bet for Tamriel. When united under an Empire, it is always at its most stable and prosperous and can best provision for the defense against the myriad of external threats the continent faces including, but not limited to, vampiric snakemen (maybe), snow demons, pirate sea elves ruled by an immoral god emperor, necromantic battle toads who once nearly exterminated all life on the continent with a magic plague and had to be defeated by their continent being sunk beneath the ocean and spoiler they are still alive, demonic beings, assorted godly beings with an axe to grind, meteors that might actually be demigods, a giant stompy robot negating everything, a normally "harmless" madgod having a sudden fancy, the byzantine politics of godly beings, the possibility that an ancient squidman empire still exists and will return to overthrow the surface world in the name of the god of rape, return of inscrutible fedora elves, etc, and then there are the internal threats both past and present that exist including again, but not limited to, a betrayed dead but dreaming god that wants to subsume everything into himself, an insanely powerful necromancer with his own personal cult that can literally strip the soul from your body and might also be a god or something, Elf Nazis, sapient possibly hiveminded trees that literally worship Kaos and may have been behind another near end time causing disease, an evil necromancer queen, breton court politics, the remnants of her supporters, her returning as something more than human, internecine strife, an impostor backed by a demon god, elf hippies turning into shoggoths, about a billion insane cults, barbarian pariah elf raids, breton court politics, the secret supporters of the previously mentioned usurpers, essentially the English cosplaying as ancient celts and are barbarians, an evil cult that worships the same demon god, imperial court politics, dunmer court politics, a super volcano exploding (not all threats need military protection), time losing the plot (ditto), potential return of the dark eldar lite, and so on.
And then there are all the trade, infrastructure, cultural benefits and the like having a united empire brings. Would you rather get brutally murdered because you accidentally stole a cup, or just be fined some paltry amount?
I think this sums up the stormcloaks,
tl;dr I am largely saying supporting the Stormcloaks is an idiotic idea, because the Empire is always a net good, even when it was at its worst. Leaving it is dumb, especially when you are splitting the Empire when it faces a dire threat- that might literally want to end the world. Also Ulfric literally played into the Thalmor's hands on Talos worship, he made it an issue when previously the Empire could pretend nothing was happening and back-door ignore the concordiat.
