I feel like mentoring is the best possible way to round out abilities as a coach. At my age, with retirement looming, I am more concerned about teaching other teachers that can go out and teach others the correct ways. There are so many things that I could never put on a website for sale or blog about that are crucial in teaching tumbling technique, motivation, dealing with mental blocks etc. Some are new off the head and others are old memories and drills that come up in certain situations. This is why having a mentor is great because they can share these things because they want to see you succeed and go father than they ever did.
It is admittedly a pet peeve of mine that when it comes to tumbling most people just want the trick. Not the process or understanding how it all works and why. That is what IMO makes you a solid instructor. Anyone can teach a kid who has insane talent walking in the door. But to take that kid that has no immediate strengths or abilities and teach them to become a pretty good tumbler, especially when others won't work with them because they are not talented - that is the type of tumbling coach you want to be. To take a nugget and make them first or last pass. To see the coaches that didn't want to work with them when they started, now beg to work with them. To see that kid that no one believed in taking the floor confidant knowing that it was not just the skills that you taught them but the mental capacity to overcome their weakness and make it a strength....that is priceless.