6. Firefly
A petty criminal turned arsonist, Firefly would have been about as different from the villains in The Dark Knight trilogy as you can get, with his obsession with fire and the genuine belief that he can see visions within the flames that he creates, he would have been an extremely dangerous villain for Batman to face, not least because of his flame retardant suit that allows him to take the heat of any of the fires he starts, something Batman would struggle to survive. Firefly was horrifically disfigured by an explosion at a chemical factory that he set alight, the very event that caused him to create his suit, something Nolan was not adverse to tackling in his trilogy, as proven by his take on Two-Face. The jetpack worn by Firefly that allows him to transport himself quickly and effectively away from Batman wouldn't be unrealistic if Firefly was re-imagined as a wealthy citizen, as opposed to a man stricken by poverty. Admittedly this would have been a large change for the character, but many characters in the Dark Knight trilogy were highly changed from their original incarnations so it's not overly far-fetched really. The more I think about it, the more I wish we had the chance to see Firefly flying around Gotham, setting fires and causing havoc for Batman, it could have led to a brilliantly dark cat and mouse game that would likely have pushed Bruce ever further towards breaking his only rule, refusing to kill his enemies, no matter crimes they may have committed. However Firefly was achieved, I would not have been adverse to seeing him in the same film as my next entry...