If you're asking if he held them back 10 years ago, when they had lots of talent, that's a fair question, but Trotz was not holding back this current team because he never had it. He was fired 3 whole years ago and, by my count, only 10 players remain on the team from when Trotz was there, and all but Rinne were 23 or younger, so only just getting their cups of coffee or getting comfortable in the NHL.
Perhaps because of that youth and maybe even an early recognition that the league was becoming more speed and skill-oriented, Poile decided to go with a more offensive system. He may've been very smart to recognize what his team needed going forward, but that's not the same as considering that Trotz was holding them back. The latter would suggest that the move was made later than it could've been made, but Poile switched from Trotz to Laviolette at the perfect time for the team, IMO. For that reason, I think that credit should go to Poile, not blame to Trotz.