He's punching above his weight class. He's 5'8" (on skates probably). He is "good", but he'd need to have some special quality to be a good NHLer. A lesser skilled player, who is bigger, will perform better in the NHL. It's evident in every puck battle, every time you protect the puck, every time you try and create room, even when skating and stickhandling.
A 6'4" player with a well built physique with Conacher's ability would be a top 6 player in the NHL, easily.