I think my avatar, the GOAT, disagrees with you on several points, like
Running
Boxing out
Using your legs
the biggest problem in rebounding is technique, not heart
Calhoun was dead wrong on running distance for basketball conditioning. There really isn't even much room for debate in this one. A mountain of aports science is behind it.
Boxing out and using your legs is debatable--a fun debate at that. I'm curious what Calhoun would think now that the game has changed so much. His biggest strength (imo) was adaptability and the game has changed a lot.
I just don't agree with using your legs. I think it comes from people's ignorance of how biomechanics works. Watch the best shooters in the world. They don't just higher when they want to shoot farther... they use their arms and (gasp) a dip. I'm not unwilling to be re-convinced on this one though.
...
Rebounding is 90% height, strength and instinct. Let's be realistic. Andre Drummond doesn't box out and is possibly the best rebounder on the planet. Certainly was 4 years ago. Great guards do not box out outside of the paint. Of that I am certain.
I am in favor of a post box out... most people are. I encourage you to watch a dozen college basketball games and see how often guards box out on the perimeter. The answer is rarely.
Tom Moore taught me the "hit and get" strategy for the perimeter and I love it. Your job is not to box out. It's to be closer to the ball than your opponent and get the ball. Sometimes that means ignore your man and jump to the ball. Other times than means hitting your man out of the way and pursuing the ball--hence "hit and get"