"This idea of fate could tie together the show's fixation on free will, birth, life, death, and limitations. I'm hoping the message of the show will involve something along the lines of Locke's faith being the source of his free will. That would be neat."
Fate is a big part of the show. Since the very beginning the show has thrown in numerous philisophical ideas, which is one of the things I have always liked about it. Anyone who has studied philosophy will be able to see deeper into the show than those who haven't. This does not necessarily mean that they are going to come to some profound philisophical conclusion at the end of the show. If you have listened to any of the podcasts or seen/heard/read any interviews with the makers, it is pretty clear that this kind of thing interests them, it is not that they have the answers themselves, they just like inserting the unanswerable questions in the show.
The writers of the show have admitted to both having read a book called The Third Policeman which they say was one big inspiration for the show. The Third Policeman is a brilliant brilliant book about a man who falls in with a con-man, the two of them plot out a murder, after the man commits the murder, he himself is murdered by him con-man friend, only he doesn't realize that he has been killed and this is not immediately clear to the reader either. After this point the protagonist is witness to all sorts of bizzare things going on around him. By the end of the book we discover that he has been in hell the whole time paying for the murder he had commited.
Now the writers have already said that the island is not hell or purgatory, but the way in which the character in the book is seamlessly transported from real life to hell is a lot like the way the characters on Lost are transitioned from real life to some bizzare island that seemingly does not exist in the real world and where the laws of reality sometimes seem not to apply. Now with the whole find815.com stuff and Naomi saying that there were no survivors of flight 815 and that they were all discovered dead, it is beginning to feel more and more like The Third Policeman.
At anyrate, I really like the show, and as long as the writers remain true to their original intentions for the ending, I am sure I for one will not be disappointed.