I don't think people got what Dinklage was trying to portray for the ghost character. The ghost is this mysterious, almost "magical" automaton. It's a machine, a very intelligent one. Dinklage gave it a proper voice IMO. Nolan's is too chipper I think, not sure how to word it exactly. The script is hard to work with possibly. There's not much to say, and a small amount of time to actually act. It's not dynamic. The ghost should be more involved, that would help give more life to the character.