I am not saying Miller is good or bad. But I am saying that a 77% win rate in Juco is not all that great. It's not bad but there are a lot of guys who had better records for longer who never got a chance at d1.
Hank Plona for example, 225-35 over 8 years or .865. And he probably would not be a D1 head coach today without a bit of luck.
There was a guy at South Plains who had good long term record over 23 years and never got a chance to be a d1 head coach.
Eric Murphy posted a 143-34 overall record (.829 winning percentage) as head coach for Florida Southwestern and just this year went to be a d1 assistant at WKU.
Steve Demeo is another with a great long term record. Never got a chance to be a d1 head coach.
There is a guy who went 46-9 in his first 2 years as a juco head coach and he went on to be a d1 assistant. Zack Settembre. He drew my attention because he is a young guy who dies his hair grey.