I saw someone post, "Joss did his funny trick again," which I thought was an apt way of summing that up. ;)

That said, I get why it makes sense for the story he was telling, and how it led to the ending that *worked*--as the villain becoming the hero at the end of the superhero story is also kind of "done." I liked it better the second time I watched it--which is actually also true for how I felt about Serenity.