Primal Rage was on my lists of things to work on, actually.
I disagree with using elements from a canceled and unreleased game, it would set a bad precedent and open the way for other similar instances. If something has been canceled, it basically doesn't exist formally.
Blizzard's feat comes from that, so it shouldn't be used. (even the profile says that)
Diablo's ending says that it begins to burn the planet, sparing only the cruel and vicious. It doesn't seem something it does in a single blow, more like an overtime feat because at that point Diablo ended the campaign and conquered the known world.
I'd be wary of using the Chicxulub event, the endings say that all gods were sealed away, underground, on the moon and else, and a lot of humans on the surface also survived the event, it's very unlikely for the gods to scale to that.
But all of this should be handled in its own thread, I can take care of revising the verse, if no one else wants, once I finish with my first first Killer Instinct revision, it's a single game so it shouldn't take me much time.