I am very skeptical of the hypothesis that Jeremy's facilitation skills dramatically improved over his four years at Duke. He has always seemed fairly limited in that regard to me, which hasn't been ideal considering his size, workload, etc. Here are his assist number from freshman to senior season.
Assist %: 16.9, 16.9, 18.7, 18.0
Assists/100 poss.: 5.8, 6.3, 5.7, 5.9
Assists/40 min: 4.0, 4.3, 3.7, 4.0
If you want to quibble about the word "drammatically", I won't dispute the point. But he HAS improved. I would also point out that the other half of facilitation is not turning the ball over, and would add these stats to those considered above:
TOV%: 19.8, 16.2, 14.6, 10.6
TO/100 poss.: 4.1, 3.2, 4.1, 2.6
TO/40 min.: 2.9, 21.2, 2.7, 1.7
A:TO/100 poss.: 1.41, 1.97, 1.39, 2.27
A:TO/40 min.: 1.38, 1.95, 1.37, 2.35
His overall decision making is better. To my mind, noticeably better, as in, I actually notice a difference in Jeremy's decision-making now, compared to what it was as a freshman.
In terms of single-number advanced stats, Jeremy was the best guard we had on the floor last year. So bringing this back around full circle, I think it is difficult to make a credible case that Jeremy's departure is a good thing for Duke. But who knows for sure? Maybe the coaches are interested in replacing him, and maybe they get super lucky (show great skill?) in the portal. There are few certainties at this time of year.