Mehrunes Dagon is the Prince of Destruction, the bloody scourge, natural disasters but also the Prince of Revolution and Ambition. Many people have differing views of the same deity, so surely some people could view Dagon in a more positive light for one of his domains? It could also be a mutally beneficial thing, seeing as how Mehrunes Dagon has meddled in the affairs of the Empire on numerous occasions. Besides, wouldn't that be a kind of revenge after what happened just 200 years ago to him?

It's the same kind of deal to artists and creative folk who worship Sheogorath. Not everyone who worships him is a crazy lunatic.

Even if they don't worship him, seeing as how the honorable Nord seem to prefer Aedra over Daedra(Akatosh, Shor, all them peoples), they could at least form a pact like the Cyrodilic Vampires did with Clavicus Vile. I have yet to see a shrine to Vile from vampires or even hear one revere him, so you don't necessarily have to worship them if you think that's a bad idea.

I don't know, just an idea.

Dagon's ultimate goal is to return to his former self, if we believe MK's writings. Sooo, he wants to destroy the world so Alduin can eat it and not go pop. Bad idea for nords.

A true Nord would never worship a heathen god such as Dagon. Besides, don't the Nords have (had) enough gods dedicated to bloody conflict? Further more, you have to remember that outside the Dunmer, Daedric worship is widely condemned and considered heinous and perverse act. Specially by a honorable lot like the Nords. This would be like asking them to seek alliance with the Thalmor.

You can't form a pact with Daedric Lords who don't make it a habit to form pacts.

The nords have their own war gods, and gods who regularly go to war. A true Stormcloak is going to fight for mother Skyrim and her gods, not these heathen daedra or the gods of the mer. Shor is watching from Sovngarde, with his warwife, Kyne, providing respite and the wind at your back, as Talos guides you to victory.

http://www.imperial-library.info/content/2920-suns-dusk-book-11