I was just wondering if anyone agrees with me that Harley Quinn should be the next villain? I think that she would be great as the "spiritual successor" to The Joker. I think it would work perfectly because Christopher Nolan said how he wants to portray villains that have yet to be in a Batman film. Also read this part of an article from wikipedia that explains how Harley Quinn became a physchopath like The Joker,
"As portrayed in the comic, she becomes fascinated with the Joker while interning at Arkham, and volunteers to analyze him. She falls in love nearly instantly with the Joker during their sessions. After helping him escape from the asylum more than once, she is caught by her superiors, who revoke her license and put her in her own cell. During an earthquake in Gotham City, she flees and becomes Harley Quinn, the Joker's partner-in-crime."
I also think that it would be really cool to see her on film, I loved her character in the Batman Animated Series.