Two issues, one which may resolve, one which may not.
The one which may resolve is this: everything you said sounds reasonable...except I am pretty sure that he was missed every single catch and shoot jumper he has taken thus far in Summer League. All of them. I am going to stick with my "he has a rep as a shooter, he'll probably come around" tact for now, but fact is you were implying he's failing because he can't go 1 on 1, when in fact he's also failing at doing the very thing you say he's going to do during the season.
The one that may not resolve is this: I raised this some days ago, but the thing is that if you are nothing but a catch and shoot off the ball guy who can also occasionally get an alley oop or break on the dunk, then you are a lot closer to Nick Young than you are to being a star. That was the curiosity of all the hopping around on draft day, and there certainly hasn't been any evidence to the contrary so far. You can see the form on the shot suggesting that will come around. But there are very few signs of the rest of it. As I've said I watch summer league for skillsets, not production. And the skillset is worrisome.