What do you think would happend if you lost and dagoth won? Im guessing we would overthrow the empire.

Dagoth Ur would remain immortal, while the Tribunal became weaker. The Blight would devour Vvardenfell, all the Dunmer would become his slaves and everyone else (all the Outlanders) would be killed. This is basically Dagoth Ur's goal.

There are mods that attempt to address some of this scenario, although not to the point of erasing the Empire from Vvardenfell. (that would be an enormous mod.)

I doubt Dagoth Ur would ever destroy the entire Empire, since it spans the entire continent of Tamriel. He would likely be content with just reigning over Vvardenfell and the Morrowind mainland.

Supervillainy 101 makes me think it would be unlikely that he'd stop after just Morrowind. The Empire would oppose him as long as they could, but given his immortality (further enhanced by all of Kagrenac's tools coming back into his possession) and an activated Akulakhan, the Empire probably wouldn't have lasted long. Working with the evil of the heart, his power would only have continued to grow.

I wonder how a Dagoth Ur controlled Tamriel would stack up against the Oblivion invasion.

Akulakhan vs Mehrunes Dagon?

That would be a matchup to behold. I'd have to give the edge to Akulakhan/Ur though. Powered by the same Heart of Lorkhan, Almalexia and Sotha Sil once managed to defeat and banish Dagon back to Oblivion once.

The Oblivion crisis never would have occurred if Dagoth Ur had "won".

Really?, I think it would have happened earlier. If he conquered the Empire, the Dragonfires would probably go dull (but then again, he would probably be smart enough to keep the mporers line imprisoned, but alive)

the destruction of that big-ass robot destroyed some tower which lead to the realm of OB openin up to tamriel. if he'd of won it'd never off happened,

:facepalm: That's right, silly me