I heard an interesting twist on the "school program matters" theme from a mid-major pitching coach this winter. He said something like (I'm paraphrasing, but this was the gist):
"It's funny, you talk to high school coach in some remote area about a kid, and the kid may be far and away the best player who has ever played there, and the coach will go completely overboard and tell you 'I think he's gonna be drafted' and you want to say to him 'Um, no, he's a marginal D1 talent.' And then you talk to a high school coach in South Florida or California about a kid, and this coach has played in like AA or AAA, and he's had multiple kids drafted, and super high level college players and the coach will be like 'Uh, I'm not too sure about him' and you want to say 'What are you talking about?! He's really good!' We always want to hear what the high school coach says but sometimes they don't have the best perspective."