On this team, the list of players to "hit back" is shorter than the players that "fold". That was probably true even when DWill was on the team.
IMO, this is why you can't trade Millsap. The dude hits back, HARD.
Really, I think Millsap has gone soft on defense. The guy he guards regularly torches him. Most of his fouls are of the very touchy variety. He gets rebounded over often.