*Plot spoilers below
I’m happy to say I was wrong about the Finale-Good clearly triumphed over Evil. There was no dabbling in grey areas or nonjudgmentalism or anything wishy washy. However, the Jack v. Locke storyline took a backseat to the “Sideways” story arc in the final episode. This seemed out of kilter because the Sideways story arc was a Season Six addition and arguably inessential to the overall story. For this reason, critics like Ross Douthat and John Podohertz found the finale disappointing because it left so many questions unanswered.
The Sideways story arc turns out to be a big Reunion as all the characters gather together before they enter Heaven together. Characters who were killed off in previous seasons reappear for one last trip down memory lane. It was nostalgic and admittedly fun, but a total dodge by the writers.
One last point about the finale. LOST is eclectic when it comes from borrowing ideas from a variety of traditions e.g. ‘Christian’ Sheppard stands in front of a stained glass window filled with many different religious symbols, the temple (not church or mosque) has Egyptian hieroglyphics, etc. Yet it borrows from the Catholic Tradition more than any other. Douthat said this back in 2007:
The creators of Lost have repeatedly denied that their characters are literally in purgatory, which was a popular theory among early viewers of the series, and most of the evidence from later episodes suggests that they're telling the truth. Still, the show's island is at the least a purgatorial landscape—it's no coincidence that several of the characters are Catholic, lapsed and otherwise—where the things that the castaways carry from their previous lives provide the raw material for suffering, struggle, and growth.
Douthat’s description seems dead on in light of Finale. Several characters were Catholic: Charlie, Echo, Hume, Richard, and Hugo. Life is divided into three stages: pre-Island, Island, and post-Island with the Island as the place where they are supposed to resolve whatever problems they had from their previous life. Some people commit acts so heinous that they are doomed e.g. Michael tells Hugo he is stuck. Others are unable to move onto Heaven because they have not worked through all their past demons e.g. Ben tells Locke he isn’t ready to come into the church (its clearly Catholic b/c it has a Sacred Heart Statue outside and Carravagio’s Doubting Thomas painting inside).
As I said before, this does NOT mean the Island is literally Purgatory. The LOST’s writers borrow from a variety of traditions and reworks them into ways which fit their purposes. But they do seem to borrowing from one tradition quite heavily. I'm sure Dante would approve.
Last, Last Point: It is interesting to see Heaven is rather Godless in the LOST mythology. Heaven seems to be about the characters’ horizontal relationships with each other instead of a vertical relationship with a Personal God. And the Island, with its impersonal ball of energy at its core, is not very conversational either. From a PC point of view, friendship as highest good is probably the best you’re gonna get from a network show. Aristotle would approve-somewhat.