What i see a very negative aspect of his game is his shot. Or very low sniper skills. There were many games in SM-Sarja U20, where he had 10, 11 and even 12 shots (but i dont know if it was Shots On Goal or only Shots attempts) and he didnt scored a single goal. This was also to see on this short tournament and even on Hlinka-Gretzky Cup. This is a area, he has a lot to work on.
For now, he is a player, who creates opportunities for his teammates. Hi can battle in the corners, he can carry the puck very well and you must have 2 players to push him away. Im still a fan of him. Maybe he is behind Nemec, but if Nemec will go as a Nr 3., Slafkovsky can go as a Nr.4 or 5.