OBAA wouldn't have been my choice for best picture, either, but it had some beautiful pieces of film-making. The long shot while running through the Sensei's safe house was great, and the car chase at the end was a) gorgeous, and b) visually not quite like anything I'd ever seen before. I can see what Academy voters liked about it, in addition to the "this director has been nominated so many times without winning, so maybe he finally deserves one" angle, which I think maybe had as much to do with it as anything.