I have a highly different interpretation of Promethea from you, because I don't really see it as actual philosophy but more as literary philosophy. Instead of applying esoteric patterns to reality, it applies them to storytelling. It doesn't try to sell a universal truth but a universal dream, which is why it did not come off as esoteric crap to me.

And I don't think S8 is a rebuke or a counter argument either. I described that I recognize some motives from Promethea and think they were done more artistically there, the central motive about a step in evolution and so on is the one were I'm inclined to agree with you though, that Joss version of this is very different. But a rebuke? I'm not really sure, because what motive is there to rebuke?

Buffy doesn't want her new world and created it out of dersperation, the people in Promethea break free from old bonds. In Buffy everyone is left behind in Promethea the apocalypse changes the whole world and doesn't leave it as an after birth.

So, while I'm fairly sure Joss is doing something different from Promethea here, I don't think he's subverting it either.