Good question. Of all the attributes that Hogwarts prizes, bravery is considered the most important. So anyone who is brave will be placed in Gryffindor no matter what other talents they possess, or DON"T possess. The Sorting Hat's song lyrics tell us this. However, that also brings us to Cedric Diggory who was both gallant and brave. Why wasn't he in Gryffindor? For that I have no answer. Anybody else have a different take on this?