This post is not intended as a knock on Brissett in any way -- kid had a great attitude, he played hard, and he was well-liked by the coaching staff and his teammates when he played here.
But I think there is a residual frustration by a segment of the fanbase by how his performance slipped in his second year. Brissett always had NBA tools, athleticism, strength, etc. but he always struggled to put it together on the court [note the shooting percentages]. Also, there was a tangible dip in his production in his second year, including a tail-off of his three point / free throw shooting -- after he'd shown promise during his freshman year on both fronts. Here's the stats:
My recollection of his sophomore season was that he started out appearing to try to show off his small forward skills by being more perimeter oriented, but the results were subpar -- so he got coached "hard" by JB to tone it down and attack more. And as a coachable kid, he got the message, but the results were semi-disappointing overall, because he didn't make the sophomore leap many expected after the strong freshman campaign.
Looks like he's ironed out the shooting, which is great. As an undrafted free agent, he was very lucky [IMO] that Nurse, the head coach of the Raptors, took an interest in him and gave him a shot. Not all 2nd round picks / undrafted guys get that opportunity.
And he continued to show improvement, even at the G-League level, which put him in position to make the most of being called up on a 10-day contract. Kudos to him for working hard and capitalizing. We need more guys in the NBA.