Yeah, well, we got the player who the Mavs were willing to trade. We have no idea whether the Knicks asked for Brunson.
Brunson had a fantastic college career. His shooting stats in his final season were phenomenal. 60%fg, 40%3pt, 80%ft. With 2 NCAA titles on his resume, he'll go down as one of the all-time great college PGs.
So with all that, he came into the NBA relatively old. Drafted at 21, he's 22 now. He was already 19 when he started college.
Compared to the Knicks:
* ~6 months younger than Mudiay
* ~15 months older the DSJr
* ~23 months older than Ntilikina.
The problem with relating age and upside is that everyone has a different development/experience curve. As a 19 year old freshman, he was averaging 24mpg and learning on a veteran college squad against college competition. He didn't light the world on fire then, but was solid and played within himself as part of a title team. Fast forward to his junior year he was the driving force for a title team. He improved his game craft to the point where he could dominate against his level of competition.
On the other hand... our Knick lottery PGs took a very different approach. Mudiay had a year of pro experience then had to learn on the fly vs NBA competition. Frank also made a bit of a leap. The Mavs saw enough potential in DSJr as a freshman that he was a lottery pick. Who knows how much he'd have grown as a player with another year in college vs a year in the NBA.
We'll never know, but according to Wikipedia, DSJr turned down Duke (Grayson Allen), Wake Forest (Bryant Crawford), UNC (Joel Berry, now in the G-league, part time with Lakers?), and Kentucky (He likely would have replaced either D'Aaron Fox & Malik Monk) to play at NC State.
DSJr with a year of coaching from coach K, Danny Manning, Roy Williams, or Calipari? Perhaps he'd have hit the NBA as a different player. At the same time, perhaps he turned them all down because most of the other coaches on this list wanted to play him as a SG.