Well, I find the possibility to be extremely unlikely, especially since such a result would rather boring for the author to write, I think. I mean, if we want to make the Mountain into a monkey's paw, all of the wishes can be interpreted in a way to screw us over. For example, the wish to change the world into one based entirely around wrestling doesn't specify whether we exist in that world, does it? The wish to gain the power to fight, stop and kill Magical Girls is based around the assumption that magical girls exist as more than fictional concepts in this world, etc, etc.
Additionally, if our story is "the greatest story ever told" then we have confirmation that our journey, out of the trillions of events, journeys, adventures and stories in past, present and future of the entire universe, ours is the best. Does that sound so bad?