I gotta say, I like this idea. I wasn't really too keen on the flashsideways, but I appreciated how they all tied it in together. At the very least it made sense. But I'm interested to see how this pans out, because I truly think that the flash sideways was more of a distraction to the actual story of the island and their struggles on it. that's what the story was about. I think the show still could have conveyed the idea of "faith" without adding in a purgatory and afterlife.