I'm a huge fan. I think Sproul has a TON of potential. He took massive steps forward this year, but it wasn't really noticed because of the Soo's disappointing season as a team.
Offensively, he got better in every area. He's obviously got a booming shot, but he was smarter in using it this year. Last year he became a bit predictable and team's started taking that shot away from him. But he made adjustments this year and really worked on getting his wrister through just as effectively. He also didn't force shots and got himself in better position for one timers. He also became more aggressive in skating the puck out of the zone, and had no issue with going deep and creating chances. But best of all, he did this while limiting some of the turnovers in his own end that plagued him in his draft season.
Defensively, lots of progress was made and this is marked by the fact that he finished +16 on the season...on a team that missed the playoffs. He used his size more and become more physical (although don't confuse him for a guy like Jarred Tinordi or anything). He chased the puck less and became a little more reserved, letting the play come to him.
If this guy were playing for a higher profile OHL team, I think we'd be hearing more about him. Definitely looking forward to seeing how he takes his development even farther next season.