Pitching is a weakness in the system, at least compared to the position side. But to say there are no prospects with upside is just false.
Aside from Perales, Wilkeman Gonzalez, and Elmer Rodriguez-Cruz have upside. There’s other pitching prospects, but these guys have a lot of upside, particularly Perales. FWIW he’s ranked much higher than Bello was when he was his age.