Ooh, really good analysis! Does make S7 fit together a lot better - not in terms of the logic of the plot, which is beyond redemption, but in terms of the sense of the story.

Chosen was also, of course, the best parting gift to fandom that Joss could have possibly left, as you can go anywhere from there...

Hah, so as Buffy was making the Slayer power viral, Joss was doing the same with the storytelling power!

Too much meta. Head go boom.