The change up at the younger ages is the most important pitch they have. As they get older, high school or college level it is still great but if it is your out pitch you give up a lot of hits. As for speed, Taryn Mowatt threw as slow as anyone and her change up was good enough to win a national championship. Cat Osterman states the rise is important in mid teens, but she became dominant when she perfected her drop. I think when calling a game you need to look at how hard the mistakes are hit and the rise and change usually fly very far when they are hit.