Cowen.
I'd love to see him take the next step with his mobility, specifically his foot speed and ability to handle puck a carrying forwards. As well, his communication with his defensive partner could use some work.
His backwards skating speed is fine but I'd like to see him be able to adjust to the tight turns of the NHL forwards. If his foot speed isn't up to the task, he could also widen his stance and lower his centre of gravity to box out forwards better. He's also not great at using his partner to organize a counter attack and breakout.
Cowen is fine when it's a small forward that he can out-muscle. He's also got great anticipation and can lay a good hit to break up a play or use his massive stick to do it, but he has more trouble with quick puck possession guys though, and his tool chest isn't deep enough to handle their moves.
He's good, but once he is able to really adjust his game to the NHL, he'll be a force.