I've been trying to write meaningful stories for 20 years now, short stories, novels, screenplays. Whatever you think of the ending, my (unsuccessful) experience of trying this informs me what the Lost writers, directors, actors, and editors have accomplished is very rare and worthwhile. If you look at it as the story of Jack, to drag out a meaningful story of a man like that and make it mostly compelling for seven years, and still be on point to the very last scene, that just amazes me.
In the end Lost was somehow very formulaic. You have the unwilling hero who gets run up a tree, rocks are thrown at him, then he comes down a changed man who's learned an important lesson. Lost just chose to make everything more cosmic, which is always an intensely risky project ... if you're not offending someone's beliefs you stand the chance of offending someone else's intelligence.
I think it's important to remember the goal is never to try to tell a new story. That's impossible. There are no new stories. The goal is to tell a timeless story in a way that people can relate to right now. And I think they accomplished that.
My hat is tipped to everyone involved. It was a trip I'm glad I took.