You need to add another layer of context to the stats and then the real story becomes abundantly clear very quickly.
Jalen scored 131 points last year; 40 of those came in the first four games of the season against very weak competition, and to take that a step further: 56 came in those 4 games + 2 more with MD-ES and Grambling. He also had 24 of his 65 assists in those 6 games.
Against representative competition, we're talking about a sub-.300 FG% with a 3P% of 15 in 27 games. From the start of Big East play on, he shot .286% from the field, .188% from 3 and scored 44 points in 22 games with a 1.3 to 0.7 assist to turnover ratio. That is not a playable high-major player by any standard whatsoever.
You seem stuck on the assist to turnover ratio, but both Jalen's and H. Diarra's are misleading.
Jalen's fatal flaw is an inability to handle high-major ball pressure. To compensate for that, he turned his back to the defender and backed the ball up the court, eating up a large amount of the shot clock. His inability to initiate offense cratered our shot quality and offense efficiency because of the number of times it led to a game of hot potato to get a shot up for whomever ended up with the ball and less than 10 seconds to make something happen when he finally got us into a half-court set.
Diarra, meanwhile, played in a Buzz Williams system that has always led to low assist-to-turnover ratios.
Remember all those great guards he had at Marquette? Vander Blue averaged 1.8 assists to 2.3 turnovers his final year and a 2.0 assists/2.0 turnovers for his career. Darius Johnson-Odom posted a 2.7 assist to 2.4 turnover mark as an All-Big East first teamer in 2011-12. These are future NBA players on Sweet 16/Elite Eight teams. Look up and down last year's A&M roster and it's the same thing. It's the way they play.
Diarra also improved considerably as the season went on last year against high-major competition. I took his final 15 games as what seems like a fair indicator: He shot 434% from the field, .378% from 3 from that point on and as many have mentioned, there's reason in Texas A&M's roster construction change during the season to believe that is not a coincidence.
All this is to say that Jalen 100% did the right thing in leaving UConn for a level where his skillset can flourish without his inability to handle ball pressure destroying his production. And perhaps more importantly, to nip any idea of using a misrepresentation of what Gaffney was to cut down Hassan before he even plays his first game for us.
