Personaly I think that Supernova is Superman's lost powers altered somewhat and taken on a life of their own (kind of like The Eradicator from Rebirth of Superman), that have a personality that is an imprint of Superman's.

Could be. Sounds a bit to much like the "Michael" thing over in Marvel.

Could be a villian trying to reform.

I looked up some previews for the week and found this;

52 WEEK #12 - She's here! The Mighty Isis is back and DC Comics has her! Or rather Black Adam does.