Why would I hate on Castle? I'm a spurs fan, I hope he'll do good. Do I believe he'll be a bonifide star? No, but I'll happily say I was wrong if he does. I'm only judging what I'm seeing hic et nunc, not fantisizing.
But the takes I'm reading here about a kid who objectively didn't have a good summer league are just epic homerism and wishful thniking (I know, just like every year). "Russel Westbrook with skills", "a better Jimmy butler..."... we went from "I'll be happy if we can get an elite role player in this weak draft" to "Castle is the next big thing" after 3 mediocre summer outings. just because the kid can somehow play BB against mostly scrubs... You can put it any way you want, 37% shooting (25% on 3) doesn't keep you on an NBA court, even if he should improve that ofc (hopefully).
You want a more objective opinion? Read what other fanbases are saying. And guess what? There's barely any real chatter around Castle, or just to mention he can't shoot. No one is saying "Crap, we missed on Castle!". And there's barely any hawk fan regretting picking Risacher over him...
but we know how it works, would have the spurs picked Risacher, everyone would praise his BBIQ, versatiltiy, court vision and be happy we didn't get that Castle guy who can't shoot instead. Same for Sheppard who showed much more interesting things than Castle.
Time will tell, but yeah, the overration is glorious probably because spurs despearatly need that seconsd star.