The mere thought of recasting a British-themed movie about a British boy with an all-American cast is stupid. Factor in that it's the internationally epic, one-and-only ultra-mega blockbuster Harry Potter and now have a garbage movie! To even suggest an all-American cast is beyond pathetic! If I were Ms. J.K. Rowling (along with the producers, directors, and actors/actresses) I'd be insulted! Alan Rickman as Severus Snape is irreplaceable, even with another British actor, let alone an American.
Sorry USA, but the red,white, and blue in this case belongs to the UK. USA missed out & messed up on this one!