I just typed up my thoughts on the finale itself and wanted to post it.
Some of it is a rehash of what I posted before I suppose, some of it has already been discussed, but just wanted to collect it in one place for myself.
Sorry it's so long.
The basic narrative of LOST as I see it:
At it's core, LOST is about a plane full of strangers who crash on a strange island (strangers in a strange land). Everything that is important to the narrative of LOST is seen through the eyes of these individuals. The setting of LOST is very important, but essentially it is a small snapshot in the whole timeline of this special island. The show was never about the creation or resolution of the island or its mystery, it was about a plane full of people who crash on this island and their reasons for being there. We saw their lives before the crash, during their stay, and the ultimate resolution of their very souls. To me, that's was really powerful and ultimately what moved me the most during the finale.
The Bilateral Ending:
In my eyes, there were two separate parts to the finale: one to satisfy the 'men of science,' and one to satiate the 'men of faith."
Plot Ending (science):
From a narrative perspective, the part of the overall mythology of LOST that pertains to our characters begins when a random pregnant woman is shipwrecked and by coincidence finds herself on our Island in 23 A.D. This is neither the beginning nor the end of the Island story, but it starts the events that are part of our journey. This women is ultimately murdered by a mysterious, very lonely woman who kidnaps and raises her two children. This confused and tormented women we later learn is a Guardian (someone who has been tasked with protecting the sanctity of this special place). Through a series of unfortunate events (that mainly was due to desperation and loneliness of our Guardian friend) one of these brothers is burden with the guilt of killing the other and by violating sacred oaths, brought into being the physical manifestation of the darkness in man - giving bodily form to the corruption inside who he murdered - and his desire to undue what he could potentially unleash to the rest of humanity. This takes place 2000 years ago and ultimately Jacob realizes his brother (Man in Black) will find a way off this island by removing him as a Guardian, and comes up with an elaborate job testing program to bring Candidates to the island who can replace him.
Our story ends rather simply, by Jack Shepard electing (very importantly, since Jacob himself was never given any choice - thus he created all these rules to maintain his Candidates free will) of taking up the reins of Guardian and finally killing the Man in Black. Desmond was needed here since he had the unique ability to withstand large amounts of electromagnetic energy, i.e. the physical source of the 'special qualities' of this Island - he was the only one who could remove the cork to seal up MiB's Smokey powers). This was his ultimate destiny and he gave his life to do it, and thus he died after fulfillment of his task. Hurley was given Guardian duty, and he elected Ben to be his "Richard" - so the two of them lived untold years together protecting the island. Kate and Claire and Sawyer with a handful of other people escaped on the downed Ajira plane and lived out the remainder of their lives in 2007 and onward. That's the end of LOST.
Spiritual Ending (faith):
There was never any parallel universe or timeline ... the bomb never worked, and as Jack said, "he's been wrong before." This was part of something the Losties faced constantly - they were mistaking coincidence and fate, and so were the audience. Anyway, The 'flash sideways' name is a red herring - what we were really watching was a form of purgatory where the souls of all who went on this Island journey in life gathered after their ultimate deaths. Here these special individuals were rewarded in death, as they got to spend some time together before their souls were ready to 'move on.' It was really touching. Michael wasnt there since he hasnt forgiven himself (or been forgiven for) for the murders he committed, he was still trapped on the island, helping out others in the form of ghostly whispers etc. While Ben is now aware he is actually dead, he hasn't finished atoning and wasnt ready for the afterlife either - he was content spending more time inside this purgatory, waiting till he was cleansed enough "being good" to complete his soul's journey. Same with the other characters such as Ana Lucia (as Desmond said, she "isn't ready yet"). That story was resolution for the 'men of faith' out there, but had no bearing on the actual story itself.
I can see people being disappointed since the flash sideways had nothing to do with the show narrative - the real resolution was Jack's sacrifice, a few people making it home alive, and Hurley ultimately inheriting the duties of Guardian ( to something we wont ever fully understand ) but the "flash sideways" gave us beautiful, spiritual resolution. They've been stuck in this place between worlds for who knows how many life cycles, till Desmond was able awaken them to accept their deaths and become aware of, as Christian said, the 'single most important thing in their lives' - the acceptance of what their fate was. They were then given peace and closure so they can move on.
I think this works brilliantly since, as they said all along: Everything on the island, happened. That was the factual events of Lost. The sideways was simply the close of our character's karmic cycle, and some people are not yet ready for resolution (Another example, Eloise Hawkings obviously was the first of all of them 'awakened' first when she saw her grownup son and having not killed him - asking Desmond not to end it for Faraday), but I loved it.
But... What about THE ANSWERS?!:
There are lots of 'mythology' stuff you can dissect if you put enough thought/discussion into it - The Others, Dharma, the Egyptians, etc - and there are lots of "expanded universe" stuff made specifically for the Internet - such as the Valenzetti Equation videos about what The Numbers are - but ultimately these things weren't seen by or important to the eyes of our characters in our initial plane crash, so wasn't touched on in the ending itself. I can see some disappointed here myself, but I think a lot of that would have been out of place given what the finale focused on.
Rambling now so will stop, but I'll miss ya LOST
