His rebounding and defense is good. He's in the 95th percentile among wings in defensive rebounding and the 72nd percentile in offensive rebounding. He's also in the 90th percentile in block percentage and 62nd percentile in steal percentage.
His problem is when the Cavs have the ball. He's in the 27th percentile in points per shot attempt and the 3rd percentile in turnover percentage. He's a turnover machine and a well below average scorer. He's hitting only 33.3% from deep, and that's where we need him to be effective.
Windler's biggest problem, besides tons of turnovers, is he's only hitting 28% of corner 3's, putting him in the 7th percentile among wings. He's also in the 17th percentile at the rim so he's pretty bad from both close and far. He's good in the 4' -14' mid-range, however, hitting 50% which puts him in the 88th percentile.
So Windler is very good at some things (rebounding, shot blocking, short mid-range shooting) and very bad at others (turnovers, finishing at the rim, corner 3's). There aren't that many things he's average at (assists per usage rate, for one).
I think he has a lot of potential. The high turnover rate is due to his not being used to the speed and athleticism of NBA players. He's essentially a rookie and he played at Belmont. The players in Belmont's conference are nowhere near NBA level. The game is too fast for him right now. Passes he got away with in college are getting stolen by the longer, quicker, more experienced NBA defenders. I think his turnover rate will go down with experience.
He should get better at shooting 3's. I think he's reluctant to shoot being a rookie and a lot of shooting is confidence. Sometimes he looks around for someone to pass to and then puts up a 3 with no rhythm instead of just catching and shooting in rhythm. He hit nine 3's in a row a few weeks ago so I know he can make them when he gets going.
I don't know if he'll ever be good at finishing at the rim but he is ambidextrous so he should be able to switch hands in the air or use a spin move and get the layup with his left hand. Right now he avoids taking it strong to the rim but he needs to do that and learn how to either get fouled or get his shot off without getting blocked.
Garland has learned to shoot layups high off the glass to avoid blocks and also use a stop-and-start move to freeze defenders. He has also developed a floater when he can't get to the rim and a scoop layup where he doesn't slow down or use his other hand to secure the ball. He also knows when to use each shot depending on the circumstances. Windler needs to learn these moves.
I think in time Windler could be a very good player because he's already good at defense and rebounding. The turnovers and 3-point shooting will improve with experience. I just don't know whether he will get that experience. He's in a Catch-22; he can't get minutes because he's not playing well, but he can't play better until he gets more minutes.