This will be a short review, but it is something I have not read elsewhere. And as a writer myself, I think I can make this statement with the proper ethos.
There is nothing more boring than a film about someone becoming a writer.
That's right. I can think of exceptions of course - Henry and June, Out of Africa. But the worst part of the past year's two "literary" films was the fact that the narrator is "writing" the book, and we have scenes where the narrator "becomes" an author. Just awful. Unnecessary. And worst of all, not accurate.
I am no purist - I love a film adaptation. The Lord of the Rings was for many years my favorite book, and I had no problems with the many changes made there. In fact, I understand completely the need to change the plots and details of books for the film medium. This is not an argument about purity, because neither of these films is too far from the book. In fact, the only part that is really inaccurate is that both filmmakers decided to make the main character a "writer." Worse than inaccuracy though, is the way it changes the story for the reader, demeans it, lessens it, makes it a reflexive story about writing, the most boring kind of story of all.
In the case of On the Road, this is somewhat accurate. Sal Paradise is, in fact, a writer, obviously based on or embodying Kerouac himself. But his "writing" is ancillary, and not important to the book's story. The key moment comes in the book and the film, at the end, when Sal rejects Dean Moriarty on a cold New York street. That is wonderfully included in the film and superbly acted by the two leads. But its emotional power is sapped by the fact that Sal is shown "writing" this scene, destroying the dramatic intensity. The director gets the film right in many respects - this is a story about men, a whole country in fact, without fathers. But the film is also, mostly, about becoming a writer. It lessens the impact, and was not the point of Kerouac's work. It is the point of far too many directors who adapt books who, because they are books, think they need to make the films about books.
In the case of The Great Gatsby, the director, or perhaps the script writer, clearly wants to show off how well he understands the book. Every theme is explained ad infinitum. This making explicit of the symbolic and metaphoric is only irritating for those who do know the book, and worse for those who are discovering it through the film. There is nothing for them to discover - there is only the surface - the implied dumbed down to the obvious. And worse, bizarrely, though there is no mention of Nick Carraway becoming a writer in the book, the director has chosen to make him become a writer, to "write" the story of the film. Thus, the film is doubly "literary" and doubly boring because of it.
It is the story that matters, not the fact that it is a written story originally in a novel form. Most book adaptations are terrible not because the books cannot be adapted, but because some directors cannot forget that they are books.