I'm not so sure it was a "character development" movie. Here's what a critic said about that: "Nolan structured the film from the point of view of the characters, intending to use visuals rather than dialogue and backstory." It seemed to me that he wanted something close to a documentary w/o it being a documentary.
I suspect Nolan was more concerned about the "big picture" -i.e. heroic rescue-than the individual soldiers. I think precisely because of this most of the awards it received were for the sound as opposed to the story telling
