Its funny, but most people take a coach for granted. Pitching coaches can mean the world to a team. I'm a HS baseball coach, but my thing is pitching, I still pitch in a 35 and over league that has some X pros in it and I talk to them all the time. You can always learn something new. Even at my old age.
I remember when I was a HS pitcher and I was a head strong kid and never listen to the coach, he sent me to old Roosevelt Stadium and Bob Feller ran the clinic, I listen but was like who was this dude to tell me how to pitch. When it was over he calls me out by name to come walk with him (I did not know he was friends with my HS coach), he spent 1 1/2 hours just talking with me, about baseball, life anything I wanted, then asked me to listen to him for 1/2 hour about pitching. Man what I learned from him in a half hour. I ended up doing what he said and became an all county pitcher in my senior year, he even sent me a note afterwards.
He did for me (not just pitching, but mentally) wonders in 2 hours, man I wish I could have had him as a coach for years to come.
I do the same thing now with my pitchers that won't listen, yes its about the mechanics, but you have to get thru to them before they will listen and learn.