Based on the title, I thought we were going to see the "Supernatural" version of the Rapture as described by evangelical Christians. After all, it is a fairly well-known aspect of many interpretations of the Book of Revelation. With Lilith breaking seal after seal and bringing the world closer to apocalypse, why not?
Instead, this was a story about Sam's growing addiction to demon blood and the consequences of being host to an angel. Both elements were surprising in different ways, but Jimmy's story was clearly the most unexpected. Misha Collins fans had to love this episode, because the actor was finally able to show some range, and he was on-screen more than the Brothers Winchester.
It was fascinating to contemplate that a vessel so willing would end up regretting the choice. There are a couple of ways to look at it, and I suspect it will have much to do with the mindset of the person making the interpretation. Those looking for the silver lining will recognize that the moral of the story is: be careful what you wish for. Uninformed choices can have terrible consequences.