I disagree. The Sifo-Dyas mystery is not as important as Anakin's dream. Based on Anakin's reaction when Sidious mentions his visions he never told Palpatine anything. He turns around surprised and says "What did you say?" And if you have seen TPM then you would know the Sith are originally thought to be extinct. And they want revenge, on the Jedi. So any casual movie-goer would assume that their extinction is because of the Jedi. The film IS meant to be watched as a final conclusion to a trilogy it's not a stand alone movie.