I think Jim Benning has done a good job. Yes he over paid on a few players, but in reality, those players under performed more than anything. They were still good players at the time of signing. They're in the same situation right now with Pettersson under performing. You can't exactly blame a GM when we're losing due to not being able to score on the PP....when the players on our PP are more than capable of doing it.
If anything, the blame should be on the players under performing, and then also the coaching staff failing to come up with successful lines/strategies to win games. I understand the team isn't using its cap space efficiently, but the majority of teams arent either, its just that the top teams have players that are actually producing as they should be.