What did these people die for, in the broad scheme of things? They died because, on the surface, Desmond forgot to push a button, which caused a surge of electromagnetic energy which in turn resulted in a plane crashing on the island in question. Fair enough. Cruel and random, desperately unfair, but appropriately tragic. But when you start telling viewers that there is a larger destiny at work, that those on the island were there for 'a reason', you'd better make sure that said reason justifies the loss of so many lives, as well as the investment of our time. When you have the main characters willingly return to the island after escaping to civilization, you'd best make their reason for returning a pretty compelling one. But why did the passengers and crew of Oceanic 815 perish? Why are Sun, Jin, Sayid, Libby, Michael, Shannon, Boone, and the rest currently buried on the island or on the ocean floor? Well, apparently they all died because Jack had to put a single rock back in its place after Desmond removed it, so that the island, an island which had two inhabitants at the time (Bernard and Rose, I will miss them most of all), would not sink into the sea. That's it, folks. Six years of hell for our heroes, just so one guy could move a rock, making a smoke monster into a man, so that another guy could toss said smoke-monster-man off a cliff and then put the rock back. All of this so the island which was nearly deserted would not crumble into the sea.
But here are the two problems. Even if you believe that said events were worth the fictional sacrifices of so many fictional characters, does anyone really trust Jacob? Because we never really got the idea that hell would rain from the sky if the Man in Black was able to escape from the island (to say nothing of the urine-river 'source', which was introduced just three weeks ago). Jacob kept telling us that Smokey was bad news, and that the world would crumble if Not-Locke was able to board a plane or boat and get off the island, but we really only have his word on that. Apparently he was wrong. Dead wrong. Once Desmond removed the penis from the vagina (which caused mystical climaxing), the inhabitants of the island, even the magical ones like Smokey and Richard, were rendered mortal. So, theoretically, had everyone just left well enough alone, Desmond would have unplugged the metaphorical hole of importance, which then would have destroyed the empty island, but would have rendered Man in Black every bit as human as you or I. Great, so Not-Locke is able to get off the island, but he can only do as much damage as any other common criminal who is smart enough to slip a bomb into a guy's backpack (sorry folks, even Allison could pull that one off). So, all things considered, there was absolutely no reason for Jack to have to put the condom back on or really anyone to have to return to the island once they were rescued the first time around. That in turn negates pretty much all of the storytelling that took place after season four.
OK, fine, you don't care that the world was never in any peril, it still works for you right? OK, but as written, the first five seasons of Lost are basically just a prologue for season six. As I feared, the giant detours that the show took at the climax of season five, both in the overly-metaphysical 'it's all about destiny/supernatural forces of good and evil' mumbo-jumbo as well as the sideways universe, basically gave the writers an excuse to ignore every mystery and/or question that had been brought up prior to the end of season five. Everything that the show told you mattered, the Dharma initiative, the Others, the character arcs of our main characters, all of that was more or less forgotten for the sake of a hastily-told generic 'good vs. evil' struggle. With the final season, the writers basically told you that none of what happened in the first five years really matters, we want you to concentrate on the epic struggle of Jacob vs. his brother. Charles Widmore, hyped as a major antagonist for the entire run, basically existed to give Not-Locke a small piece of exposition before being shot dead by Ben. And how about that compelling end-game for Johnathan Locke? Oh wait... he really has been dead all this time, and in the end he really was a pathetic, delusional vessel who was fated to be arbitrarily murdered in order to scare the other survivors to return to the island for reasons that were left unexplained for nearly two whole seasons. I'm sure glad we invested our time with that major character. In the end, our favorite believer was a glorified red shirt.
As for the sideways universe, I didn't figure it out until right at the end, but that was only because I didn't realize I had been lied to. From the beginning, the first theories of Lost involved the island and/or the stories being told existing as some kind of purgatory. And from the beginning, we were assured that it was not the case. So yes, the creators invented an entire parallel time-line which consumed much of the final season purely so they could actually deliver on the promise of 'yeah, they are all dead after all'. Except unless you figured it out early on in the episode, the emotional moments of the flash-sideways scenes had no impact. After all, if we believed that both universes were true and equally valid, why would we care when certain characters discovered what their lives were like in a parallel universe? If you believed that both worlds were real, why were Sun and Jin so overjoyed to realize that in a different time-lime, they ended up on a deserted island, got separated, had a child, and then drowned together in a submarine? And if you believed that both worlds were true, why was Ben apologizing to John Locke for actions he committed in a different time-line? "I know in this world I protected you and befriended you," says Ben to Locke, "but I'm sorry I strangled you to death in a parallel universe." Considering how crappy most of the 'real' lives of our island friends had been, why were they so happy to be ripped from their comparatively idealistic afterlife to be reminded of the hell that they had went through? "Gee," thought Mr. Echo had he been around, "I'm loving my life right now as a peace-loving priest, but thanks for reminding me of my horrible, forgotten childhood as a brainwashed child soldier."
And all of this just comes if we take what we saw at face value, which if course may not be the case. But what we are otherwise left with are simplistic notions of sacrifice and redemption, complete with the idea that the ditzy-blond you boned for two weeks can be your soul mate as opposed to the actual love of your life, and how quickly you can accept your tragic fate and move forward is directly proportional to how big a star you were in your island adventures. The finale didn't matter because the story it told was seemingly invented from whole cloth at just the start of this season. By creating a whole new mythology in its final season, in a failed attempt to give the show 'deeper meanings', the series chose to ignore everything that viewers had become invested in. It takes a certain chutzpah to craft a finale to a long-running series that purely centers around incidents revealed in the last four episodes and the revelations behind a narrative-strand that was unveiled at the start of the final sixth of the story. Hell, even the X-Files did a better job of tying up nine years of mythology by the time it ended, and Chris Carter was even smart enough to slowly close the book on various story threads during the last four seasons (destroying the conspiracy in season six, resolving the mystery of Mulder's sister in season seven, etc). By leaving everything unanswered right up to the end, and then pulling a narrative switcheroo instead of finishing the story that was being unveiled, Lost basically mocked those who bothered to watch from the very beginning, as such rabid viewership proved entirely unnecessary. Thus, the finale of Lost rendered the entire series run relatively pointless and effectively killed any and all rewatchability of the prior episodes.
So, in the end, Lost ended for me with season three. The three later, abbreviated seasons no longer count. The show didn't need an endless parade of island invaders that arbitrarily tried to kill our heroes. The show certainly didn't need a return trip to the island, which left the cast randomly wandering around the island with no direction or motive for nearly an entire season. The show didn't need the confusing time-traveling, which rendered the actions of the island inhabitants pointless since they could jump through time at any moment of peril or triumph. And the show certainly didn't need a last-minute infusion of old-school religious parables, with newly introduced characters as angel/devil stand-ins in order to give our islanders some manufactured higher purpose which in turn robbed the show of its quasi-plausibility. The show as I know it ends at the end of season three. It ends with Charlie sacrificing himself so that everyone else could get rescued. It ends with Ben defeated and Locke choosing to stay on the island in search of a purpose that would never be revealed. It ends with everyone who choose to leave apparently off the island, but still just as miserable as when they got there in the first place. Thump... Oh well, hopefully 24 will end on a superior note.