Nice to see everything coming full cycle, especially in the very end by Jack closing his eyes in the jungle, just attended by Vincent to not die alone.

As a WoT fan one also can't help but note the likely similarities in the mythological inspirations regarding the Island-plotline ending: the Candidate/Dragon with a bleeding wound in his side descending into a Pit (of Doom) to close a Bore by giving his life.

IMO, it was also a clever ruse by the writers to make the side-flashways a purgatory, after so many people believed that the Island was one.

Finally, I think the union of most of the main characters in this church (basically an all-religions-combined "terminal lounge" till you "fly" to your heaven or other afterlife?) was consequent, considering the mix of all various myths and religions, etc., in the series before.