I can see why there is a growing trend in the analysis of the finale that critics find the whole ending badly constructed by the writers. It was like the saw horses were put in the lanes, but the workers were no where to be found to actually fix the roadway. Trying to map out any true cohesive concepts and character lessons in Lost is becoming harder and harder.
In construction, people plan out everything on blueprints and drawings to connect all the pieces to form one solid structure. The same holds true for story telling. If a writer creates a concept, he or she needs to make sure the action explains the concepts in a meaningful fashion. And if one fashions a concrete idea, it needs to be strong enough to hold the weight of criticism.
There was little foundation for the concept of the sideways ending. If the characters "created" the sideways world to "remember the most important thing" in their lives, why would they "forget" the island events in their own sideways world? It is a baffling contradiction.
Well, some would say they had to "remember" or be awakened in the sideways world. Then, if you "forgot" about the place to meet in the after life, then how could you "find" it? To become awakened presupposes that you know where to be at the right time; and the inference is that the sideways world was not the next normal place for souls to go after death.
Plus, if the characters created the sideways world as a fantasy holding tank until everyone else arrived, why did early arrivals make such stupid choices? Example, island dying Juliet's last words were to her love, Sawyer. But in the sideways world, she is Jack's ex-wife. Why is there no carry over of her emotional last moments on her soul into her sideways story line?
The same goes for Kate. In her sideways world view, would she not have at least sought to rekindle the happy moments of living with Jack in the O6 time frame? Especially, since there emotional departure after killing Flocke on the island?!
And why would Jack's sideways story focus on a life and son with Juliet? One could rationally see Jack trying to make things right with his first true love, Sarah, in the sideways gambit. That would make more sense than a cordial divorce with a make-believe son with Juliet. If that is what his subconscious wanted, then why did he immediately move on with Kate?
The whole "love of one's own life" concept is totally destroyed by the Sayid choice. Shannon. Really? Every season Sayid's story centered around Nadia. She was center stage in his sideways story, too. But a two-week island fling with Shannon trumps a life time of yearning? For many, this was the most disappointing aspect of the church reunion resolution.
And there is a real core sadness, too. If Hurley's only love was Libby, whose only true romantic "quality" time was in the make believe sideways world, then Hurley lived a sad and lonely life. Then add to his story the fact that Boone and Locke showed up to the church with no one to share the moment - - - how sad was their lives? Dying in the island time frame was the "best" thing they had??
And how the show treated children was center to some people. Was Aaron's most important time of his life the island? Was he merely a "prop?" Was David just a figment of Jack's daddy-issue imagination. What ever happened to Emma and Zach?!
For the finale was supposed to be all about the characters, "character" was lacking in the end. Did they know it was fantasy land with no consequences? If the sideways world was purgatory, a place where one is to seek redemption, then it was a total failure. Example, Sayid kept killing people, Desmond severely injured people, and Ben kept scheming people. If you compare the island and sideways characters, there was no dramatic change in the personalities, their motivations, their sins. The end did not have a soul cleansing reunion but a mere show cast party.
So what were the BIG changes to the characters in the finale? What were their individual spiritual realignment moments? How were these lost souls found?!
Nothing. They just died at some point. That's all. Nothing changed in their collective behavior, conscious memory, or even in their dream fantasy world. Even though cloaked in religious overtones, there were no rewards for being "good" and no punishment for being "bad." The characters remained essentially the same, like raw materials being fed down a cosmic processing plant.