I think Mattingly's philosophy can be seen all through this list - more players who are high risk/high upside.
Miller is a good example, gamble on injury, fixing minor swing mechanic issues, start him as SS more to make him more valuable as a 3B who can move to SS in a pinch than a SS prospect (Rincon, Caba, et al are better bets). Plus get him more fielding reps. Not as safe a pick as Bohm but more upside.
Its a double gamble, more big swings but also a lot of investment in resources to increase the odds of "contact" with those big swings.