This reminds me why I have come to dislike overarching 'threat to the world' storylines. They wrap everything around themselves. Hard to have fun player initiated heists, hard to even worry about your insignificant personal woes; the world is at stake, man, whatcha gonna do?
Though I have a funny story regarding an unusual course such a scenario took from years ago. Perhaps it was accidentally very Story Now in a sense?

It was an Exalted campaign I was running and a Deathlord was trying to blow up the world. The motive of the Deathlords is basically to end suffering by euthanising the entire world. The PCs somewhat unsurprisingly were not going to let this happen. So one of the player characters had dragged her wife (who was originally just a random NPC but the player decided their character madly falls in love with her) into the 'final battle' with the Deathlord. In the ensuing battle the wife gets killed (I don't remember how, probably due random. The wife was a competent warrior, but not nearly as tough as the PCs.) So at the crucial moment where the characters are just about to stop the bad guy from activating his doomsday thing, he makes some sort of classic villain speech, addressing the character whose wife was killed. "Now you know my pain, join me and we can end all the suffering forever!" (Or to that effect.) So the character, who is utterly heartbroken, actually agrees, joins the bad guy, the world gets blown up, the end.

On the one hand it was pretty cool, but the other players weren't terribly pleased.