I don't think it's normal for a typical pitching coach/organization to have similar before & after results Katz had with guys like Giolito, Crochet, Cease and Rodon. Every time he had success with a legitimately talented pitcher they were traded away. Fedde's career basically fell apart (again) after the Sox traded him away, FWIW. Whether you want to credit Bannister or Katz for his success is a fair question.