I went back and forth on Black. I do think it was fair to bring up the question of, "is Black even a PG?". Obviously not all PG's are the same, positions are just labels, but some of his skills were suspect imo. I thought he was really good at getting to the basket (and getting to the FT line) with the ball, but I do think he lacked certain qualities that most NBA's have. Obviously the lack of shooting, especially off the dribble, made it a big question mark if he could ever be a leading ball handler. I was also concerned about his POA defense as he was consistently getting wiped by on ball screens and getting blown by with straight line drives against smaller players. On top of that, he was getting a lot of comparisons to truly elite pass (Lonzo, Giddey), but I do not think he was on that level. A big part of his case was that he was a big PG....but were his skills good for a PG, or just good for being 6'7? Time will tell, but he might get caught in between where he's a big PG with below average skill or just an average sized wing with plus skills.
That was a tangent, anyways....
I have Castle on par with them. The size/athleticism difference between he and Black is marginal imo. I wouldn't say Castle is more polished or skilled than Cason, but he's bigger than him and more polished than Black. I think Cason has the most PG, but I think all kind of fit a similar place on the team. I find it hard to separate their levels. IMO, the thing that those two had that Castle does not is defensive playmaking. Castle's stocks aren't terrible, but that aren't nearly as good. I see him getting a lot of good reviews for his on ball defense, but that's something I need to watch more film on to form a true opinion. But I'm always a little skeptical of "good defenders" that don't have great stocks. The overwhelming majority of good perimeter defenders in the NBA were high stocks guys. Not all of them, but most were higher than Castle. If I feel confident that Castle can be a strong, versatile defender across multiple positions I may have to move him very high.