Under Gord Dineen, the Marlies were 26th in the AHL in Fenwick close though this is counting 67 games only. Now maybe part of it was using Carlyle's system
However under Steve Spott, the Marlies were I believe a top 15 team in possession. They also used Carlyle's system. Coaching plays a bigger part with how a team plays than you may think. Than of course the special teams play under both coaches was night and day
Under Spott, they were an above average PP team, and a good PK team
Under Dineen, they were terrible in both, and one of the reasons they were ousted in the 1st round
Now lets look at Sheldon Keefe
Under Keefe, they Greyhounds were the 4th best team in the OHL in terms of Fenwick close. They had the 3rd best PP, and were an average PK team.
Not knocking Dineen or propping up any one, I believe Gord is a better assistant coach than a head coach. If my memory serves correctly, when he was assistant coach, he would handle the PK which was pretty solid under Spott and even Eakins
We are going towards a puck possession approach which is great as a lot of the great teams have a good puck possession system and that is a big part of their success