2. Hush
Hush's real name was Thomas Elliot, a childhood friend of Bruce Wayne, who would often outmaneuver Bruce during the strategy based games they played. Unbeknownst to Bruce, Hush was also a dark reflection of himself, similarly to Prometheus. Hush first developed feelings of hatred for Bruce after he tried to kill his own parents so that he could inherit their fortune, but they were saved by Thomas Wayne, Bruce's father, for which he blamed Bruce. Hush could have been an interesting villain in the same vein as the role he played in Arkham City, killing people on the streets of Gotham after disguising himself as Bruce Wayne thanks to his incredible skill as a surgeon. If Hush was included in this way, it would have opened up a large number of possible storylines, although it is very unrealistic to believe that his surgery could be perfect enough for people to just accept him as Bruce Wayne, he could carry out his crimes by night, making it harder for witnesses to realise that he was in fact not the real Bruce Wayne, something which could eventually lead to the police even arresting Bruce for the crimes that Hush was committing. Hush was originally aided by the Riddler, which would have made him even more formidable, and it could have been possible for him to be a part of my aforementioned plot ideas, as a further accomplice of Riddler and Firefly, although it may have come dangerously close to over-running the plot with villains, Nolan would no doubt have managed to pull it off perfectly. Hell, if I had my way I'd have had a fourth film in which this plot took place, Bruce arrested for Hush's crimes as he attempted to stop the reign of crime he was creating with the Riddler and Firefly, whilst Calendar Man played a consulting role in Blackgate, before helping Bruce to escape from the inside, after growing tired of being seen as a joke by other criminals. I also would have had Hush's true motives hidden from the Riddler, with him eventually stepping away from their allegiance to take on Bruce at the film's climax. But well, that's just me, and there's still one more villain I'm yet to mention at all yet...