Gordon-levitt would be a really good Grayson! hes the right size and has the right look..and the boy can act! that would be diving in to the batman R.I.P story arc which would be bad a** to us comic book fan! but universally the average movie goer won't get it
But then again the beauty of Batman is that he is a Symbol. he doesn't even have to be shown out of costume. leave the rest up to the Imagination. Kinda like The teen titians Cartoon...we all knew it was the d**k grayson Robin..but he was never addressed by his real name or really shown out of costume...but we got the idea.