Premises: Starting Off On The Right Foot?

So Fallacy, Pseudo and I had this little exchange of ideas about one of the tab RPs we saw starting up, so I decided to take it here.

It's well established that the introduction post of an RP can make or break it, but what I'm looking at is what led up to the events in the story, how the world got to be in such a state that the four Warriors of Light must awaken from their hundred-year sleep and take care of the Sealed Evil In A Can once and for all. I'm talking, of course, about the premise of the story, and perhaps how feasible the events in such a "prelude" should be to foster good roleplaying.

My point of view is that it doesn't matter how outrageous the event is that kicks off the story: It's already happened, and the story is about coping with the changes that happen in the wake of such incidents. Of course, feedback is appreciated.