Not sure what you're trying to say here. Three returning starters are good or great shooters (Sexton, Cedi, Love), and overall the Cavs were a pretty alright 3-point shooting team last year. Plus, Goga's one of the best 3-point shooting centers to come into the NBA...and 3-point shooting centers are much rarer than 3-point shooting wings.
Also don't agree that KPJ has higher upside than Windler. I think people are assuming that because he has this checkered past and difficult personality there must be greatness somewhere underneath. But what if there's really just mediocrity underneath? He didn't even have the one token 30-point outburst you expect from that kind of prospect. His season was just a dozen or so highlight-reel plays with a whole lot of bad basketball in between.
Cedi is above average as a shooter hes not a good shooter yet. Cedi of course has upside to become a good shooter. Beilein likes to have 3 to 4 shooters in any given lineup. Adding Garland, Windler, Kevin Porter Jr. allows him to have much more flexibility.
As for higher upside KPJ was top ten on the Cavaliers draft board according to both local and national media. I am not saying it because its what I think but because its been reported as such. KPJ has a low floor I am not in disagreement with that. But his ceiling is higher then Windler because he can create for himself some even called him the best iso scorer in the draft. He played 22 games in college, 18 of which were after injuries/suspensions he never got to get into a rhythm. His ceiling is sky high but his floor is below the basement. To argue Windler has higher upside is crazy, too say Windler has a much higher floor would be correct.