Wha…? Whatever Nolan does (if he directs the next film) will bear no resemblence to what has come before so why not have Selina Kyle (I never said Catwoman) in the next film along with a very different Penguin? And who said they would be paired forces?
It is not my preference to have all or any particular combination of characters in the next film, but I liked the world of the Dark Knight being inhabited by several villainous forces. This film was not Batman vs. Joker. It was the Dark Knight vs. the criminal forces of Gotham.
The “Dark Knight” has an ensemble of villains with varying degrees of importance including Scarecrow, Two Face, Joker and Sal Maroni all classic Batman characters. Three relatively big ones.“Batman Begins” contained the famed Ra’s Al Ghul, Scarecrow, Carmine Falcone and of course Joe Chill. Of course many of these in first film are lesser-known to filmgoers, but comic book fans know each and every one.
You never run out of Batman bad guys.
One thing I don't like about the new Batman movies is that all sorts of villains are just thrown in there and some don't have a point, they're just there like the Scarecrow who I thought was a complete waste of a character in Begins. Atleast in the last four Batman films before Nolan came out with his version of Batman that the directors had a lot of time in the movie devoted for the villains like Two-Face, Freeze, Joker, Catwoman, Riddler. They weren't just thrown on screen for the sake of having them show up. The directors showed how the villains came to be, why they're messed up, etc.
For example, Michelle Pfeiffer's character wa sa lonely secretary. She worked hard but her boss at the end could have cared less about her and pushed her out of a window. She had no friends, no love life, just her cat. Once she got pushed out of the window, she woke up with the feeling that she had to change into something else because her past life was horrible. Hence why she became Catwoman.
The Joker, Jack Nicholson's character, had ambitions of taking control of Jack Palance's gang but for the longest time plated the number 2 guy. He was also messed up in the head, according to Keaton's Batman while reading his profile. Once he woke up as the Joker from falling down to a thing of chemicals, he killed Palance and took over the gang, and wanted to kill all of the people in Gotham, while dancing to a few Prince songs too.
With Nolan's movies, the villains are just there, like the Scarecrow. the Joker shows up but we have no idea why he wanted to become the Joker, although he told people two different versions as to why he became the way he is, as a joke to himself. (Maybe that makes Nolans Joker more scary?)
But that's just my opinion.
But for pairings, if Nolan had Ra's and Scarecrow working together, and Joker and Two-Face working together at the end, then with this same formula Nolan would have Penguin and Catwoman teamed up together in some form.