Two questions...
Is John Blake the boy who was at the balcony in Batman Beggins when batman gives to him the gadget? (the same with Rachel at the gas attack?)
How old is John Blake?, assuming that he watched Wayne's visits to the orphan house and also that he probably was 17 or almost 18, must be 8 years older, lets say 24-26 years... Isn't old to be Robin and according with Nolan. Robin at Batman Begins was in the cradle.
I think that Nolan mess it great introducing Robin. My personal comment is that it should have been Azrael...