I'm disappointed that Grant Williams isn't going. That guy should be getting as much organized basketball time as possible.what does this have to do with the summer league?
Cute, but yes, one of the main advantages of the young or new players participating in the summer league is to start to learn team systems or just in general, get used to the speed of the game. It is not just about developing individual skills. In fact, it is probably not that great of an opportunity to work on individual skills.
I can see holding Grant (and Robert) Williams out of the summer league. They have played in the league enough and know the Celtics' way. I would like to see Moses Brown there though. Even if it is just to get to know the other players (basketball and personally) and start to learn the Celtics' way. A chance for Pritchard, Langford, Nesmith, and Moses Brown to play together would be very beneficial to them as a group as much as for individual development (and Edwards to some extent). For Yam Nadar it is more of a try out so his situation is a little different.