Lost does pretty much everything right for a TV show. It has good character development and good plot, and a twisting storyline that makes you come back for more. I know some people might not like the "must-follow" status, but frankly, sometimes single-episode stories get boring and predictable. It's downright good marketing.
Anyway, on to my thoughts about the finale. Despite getting in everything it "needed"--emotional and structural resolution, good action scenes, and even a curtain call for most of the old characters, it didn't put them all together perfectly. Not that it was a bad two and a half hours, but it could've done better. And don't ask for a more detailed answer either. It was just the feeling I got.
The one thing that really left a bad taste in my mouth, though, was the scene where Jack was in the "prayer room" (not really sure what to call it) behind the church sanctuary. Behind him was a glaring stained-glass window with symbols from all the major world religions: a cross, a yin-yang symbol, a eight-spoked wheel, a crescent, and more. The rest of the room--and church--looked particularly Catholic. It was obviously a message, one that I really think didn't need said--that your past deeds don't matter as long as you choose the right side in the end, or more specifically, all religions lead to the same place.

Until this, Lost has included many blatantly Christian parallels or allusions. One character takes his role as a Christ-figure seriously (trying to avoid spoilers), one of the "demigods" on the island is called Jacob, and he is locked in combat with his unnamed twin. A promotional picture for the final season showed fourteen of the characters set up like they were in the painting "The Last Supper."
So my mom said maybe they're trying to give "equal air time." Maybe this is true. But I don't like it anyway. Lost has always offered heavy topics to think over, such as free will, fate, and faith. Now, it gives non-believers even more questions and problems.