What a great analysis of the complex and emotional journey that Lost represents! Being a fan of the series myself, I totally understand how exciting yet disconcerting those twists and turns can be.
That blend of surreal sci-fi with the emotional depth of the characters is what makes Lost so special. The ability of the writers to weave together such different things as time travel, scientific experiments, and such human themes as guilt, redemption, and the desire to belong is simply masterful.
About the last season and the flash sideways, I was fascinated by how they introduced that alternate dimension, although at first it also left me a bit confused, especially with characters like Sawyer in his role as a cop, which completely breaks with what we knew about him. But right there is the magic of Lost: not only does it lead you to wonder “what's going on?”, but also “why does this make sense emotionally?”. I think Sawyer's journey as a cop somehow reflects his subconscious desire to redeem himself, something that was always present in him, even when he was a con man.