I totally agree with your assessment of what makes a good coach.
I have always said that Larry Bird would make a better coach (and did) than Michael Jordan ever could dream of. Why? because it came so natural to MJ that he would have a very hard time teaching it to other, less talented, players. Counter that with Bird and all the stories I have read about what made him so good was all his tireless work in the gym because it wasn't as easy for him.
I think the same thing can be said about how Ganz relates to QBs. He was good. But, he wasn't this 5 star player who came out of HS and rolled right in and succeeded at the next level. He worked his azz off and right up until the first game he started, most Husker fans thought he would never amount to anything. He can now take that experience and relate to every QB in the system.
Now...as far as Bo's system. I have no idea. The big question to me is.....how much more difficult is his system than what is being ran at other top programs. If the answer is "not much" then it isn't the difficulty of the system that is the problem. Now, if other very successful programs (on defense) have a much more simple scheme and let's the athlete play, then it's something that needs to be considered.