Re: Who is the main villain of this movie? *SPOILERS*
Catwoman worked because she wasn't a straight up antagonist. More of a tweener of sorts and that's kind of a stretch to a degree. But I definitely love that about Nolan's trilogy too. I love how there was always this kind of pyramid or hierarchy when it came to the villains:
Carmine Falcone > Scarecrow > Ras' Al Ghul
The Dark Knight:
Sal Maroni (or you can just say the entire mob) > The Joker > Two-Face
The Dark Knight Rises:
John Daggett > Bane > Talia Al Ghul
TDK one I'm sure people will disagree with how I put that one together, but I had Two-Face over Joker only because The Joker pretty much creates Two-Face, which expands on the freak idea. But obviously The Joker was head honcho when it comes to villainy in the film. That's a given.