Re: The Joker sized elephant in the room
If the sixth rule is most important, why does Blackgate need to be dedicated to Harvey? Why do they need to mention Harvey at all, both of the Nolan's when asked to confirm Two-Face's death said his death was the end of his arc, yet here he is being mentioned several times in the film.
If Joker isn't mentioned, that's cool, Batman would have other things on his mind and wouldn't necesarrily bring Joker up, unless talking to Gordon or Alfred and comparing him to Bane. But people will want to hear it, most people went to see TDK because of Joker and Ledger and due to his magnificent performance it would just be strange to mention every other major villain except Joker.