Bill Sy: Jaylen Brown had more turnovers than assists due in large part to his loose handle. He was spectacular around the rim, but so many times last year, he was stripped of the ball or committed some unforced error off the dribble. In his YouTube series, "Hone the Pressure, It Makes Diamonds," you can see that he's really working on it this summer.
Mike DePrisco: I'd really like to see Terry Rozier refine his finishing around the rim. He has the quickness and dribble moves to get to the rim at will, but he struggles to cap it off with two points. There are times that he looks like Kyrie Irving until he botches the lay in.
I think the increased confidence he'll develop from improving that area of his game will help the other aspects of his game like defense, playmaking, and perimeter shooting.
Greg Cassoli: I know he hasn't played a single game yet, but I'm already hoping for Jayson Tatum to improve his shot selection. He's got a lot of nice moves, and can make some pretty impressive buckets in isolation, particularly in the midrange, but unless a player can make those shots at a truly elite level, they tend to be inefficient. If Tatum can get looks within the flow of the Celtics system, and go to his bag of tricks as a last resort, he could be a very useful player, immediately. He didn't show that kind of discretion in Summer League, but he also wasn't surrounded by the type of talent he'll be teamed up with this year. That should benefit him, but I'm betting it will take him some time to figure out how to make things work just right.
Bill Sy: Let's talk about Marcus Smart. No, I'm not going to mention his outside shooting even though there's a lot of summer work out videos out there that show his improved stroke. If he can hit the 3 next season, that's gravy. What could serve him more is a floater inside the paint. He's already fairly effective in the post, but I'd love to see him use his running back body to get in the lane and finish with some finesse around the rim.