Quantifying overall individual defensive impact/ability is the most difficult thing to do from a basketball analytics standpoint, imo.
Davis is better defensively than any of the numbers say he is. Had some to do with ND’s defensive style, some to do with what he was asked to do individually, some to do with the players around him.
I like Miyakawa as well and think he adds a lot of valuable information, but you can’t scout a player or team solely on a spreadsheet no matter how many new adjustments you make or how hard you try.