A few things to think about in regard to that.
1) Morrow was 24 and had already played a season in the league- a very productive rookie season. Mitchell is 20 and a rookie - speaks to ceiling and potential for improvement.
2) Morrow followed that summer league performance up to become one of best shooters in the league for the next 3 or 4 years. In the regulat season, he shot 47% from 3 in 2009, 46% in 2010 and 43% in 2011. So that SL performance was an indicator of success in the League. That kind of shooting is elite.
3) Morrow, even when he was good, was all about offense. Mitchell's offense is icing on the cake. Mitchell's calling card is his lockdown defense. If he only averages 10 ppg at his best, with his ability to defend its still a win for the Jazz.
Even prior to the draft he was thought of as the best defender in the draft. What excites me most is that the best freaking defender in the draft, probably in all of SL, just dropped more points than anybody in the last 8 years. Your point is solid, however. We do have to take SL somewhat with a grain of salt, but there are a lot of damn good players in this SL and in past SLs who couldn't do what Mitchell did last night.
Sent from my LG-K540 using Tapatalk