Hello Audience.... I'm one of the multitude.
Supernatural has reached that point where heaven is basically on Earth, Hell is in chaos, and the questions regarding law, anarchy, good, evil, faith, judgement, redemption, absolution, and holiness as a spiritual fortitude is left in question. After the questions we see in the television show that there is some kind of war on Earth.
In Supernatural we have Angels acting like Devils. The TV show has cast Demons into role of near saints. We can see that there is a potential for complete destruction upon Earth that hasn't been rivalled since the catastrophic collision between an infant Earth and Thea. Was there life there before? There was life after. For the Winchesters there isn't a distinction between Devil and Demon. For Earth and the Supernatural myths there is a consistency challenge. Beyond consistency challenges there has to be some kind of need to attach a hope of redemption for all religions to this theme park.
Purgatory is the infinite abyss where all the unordered souls of beasts, monsters, some demons, angels, heroes, and villains go.
If this alternate reality has been created by some greater being.... it most certainly explains the fall of the Old Gods. The Old Gods were never really gods... they were just animals that were part of the environment. That's sad; but it can work for entertainment value across a number of continents.
How do you save Heaven?
You can't have it on Earth.
I think there might be an opportunity to use Crowly in a dramatic opportunity using Phil Collins's song: Air Tonight. Where some universal conjunction of stupidity might come together to save Earth without a “God” character directly using some fantastic intervention. Please use Castiel... the character was allowed to act with the power of an absolute god.... for a time. Castiel really should be the super-hero in this mix. Crowly should have the opportunity to demonstrate his own need in the universe. You have 'Purgatory'.... and all it's horrors. Heaven and Hell might have a reason to need to co-exist.
On a personal note: I'd like to see you use the Prometheus Myth to swing a saving moment for the value of humanity and it's value as a potential higher order to both Angels, Demons, Devils, Heros, Saints, and rampant Souls.