The Ace of Knaves said:
Like who?
Is Bale a leftfield choice? Is Neeson? Is Morgan Freeman? Is Gary Oldman? Is Michael Caine?
No, they ain't.
The closest you can get to leftfield choices so far is Heath Ledger. But Nolan didn't go "Hey no one would expect Ledger as the Joker! Let's cast him!"
Nolan chose Ledger because they both had similar ideas when it comes to portraying Joker in the world Nolan created in Begins. That's it.
Mind you, Wilkinson, Oldman and Murphy were somewhat left-field. They just didn't bring so much focus on themselves as Ledger did.
Bale wasn't a left field, but it wasn't a big celeb either. Major points for the fan online movement that banded together to support that inspired and non-typical choice. To be honest, I don't see that happening now.
Neeson was a predictable one, but Nolan played on that predictability to enhance the twist. Although we have seen Neeson playing a mentor multiple times, we haven't seen him playing a bad guy often. Same goes for Eckhart, predictable Harvey Dent, left-field Two-Face.
And then there are all the relatively unknown actors (Mark Boone Jr., Linus Roache) and has-beens (Rutger Hauer, Eric Roberts) that usually fill secondary roles. I've seen some big names here being cast for the most secondary roles, just because people want to see them in the films, not minding all the attention that would go to them.
Despite all of this, I do agree with you, some people read too much into it. It's not an unbreakable rule for him. But he
does have a knack for some left-field casting (i.e. David Bowie).
IMO, Nolan just likes to mix it up... and "
Imsomnia" was the perfect example with totally cliché Pacino and completely left-field Robin Williams. Nolan's record makes hard to predict anything.