Meh.
I mean, which is more important, Bagley being the admitted-by-the-author "most dominant player in the country" over an entire college season as a freshman, or a handful of lackluster Summer League games? I'll take the whole college season as probably the better indicator of his ability, thank you very much.
And by the by in regards to the article, how about this:
Umm, let's be real here. Randle shot 17% on 18 3PT attempts in college. Bagley shot 40% on 58 3PT attempts. Yes, that's exactly the same and indicates that Bagley will be a disastrous three-point shooter. Jeez.
Let's imagine that you told me that given the fact that it was his first rodeo and the three point line is a bit deeper than in college, that Marvin Bagley's "true" 3PT shooting percentage over his rookie Summer League would be 25% if he were to replay it over and over. That seems reasonable to me, given his 40% shooting in college on a good sample size and and a good-looking stroke. 25% just isn't too high. OK, so this time around, Bagley was 15% too low on a whole 10 shots (1-10 actual). Well, he's just as likely to have gone 15% too high, so over the long run there would presumably have been as many rookie Summer Leagues where Bagley shot 40% (4-10) from three. And seriously, if Bagley had shot 40% from three in Summer League, we'd be twisting ourselves into Möbius strips waiting for the season to start.