Why John Blake?
I remember Nolan saying in an interview that he'd never introduce a Robin in the movies, then he comes up with Robin "John" Blake whose origin is somewhat similar to Dick's. I loved the movie but would it kill Nolan to introduce Dick Grayson instead? Have him be a guy who grew up in an orphanage and eventually became a police officer. And have him find the bat cave at the end of the movie. Why come up with a new guy? I know I would've loved to see Grayson in the movie even with a slightly changed origin (not like other characters' origin stories are 100% true to the comics). So why not do that instead? The guy who played Blake would've made a nice Grayson too.