When we talk about "top coaches" it's important to distinguish between great coaches and coaches with great gymnasts. A great coach is someone who can help their gymnasts, in order of priority: 1) stay safe, 2) enjoy their time in gymnastics, and 3) improve their skills. Nothing in there about reaching a high level or winning meets. Women's gymnastics has an expiration date, folks...very opportunities to continue in serious training past age 18, even fewer past age 22. The experience and the process of learning gymnastics is so much more important than the "end point" because every gymnast's competitive career has one of a few end points and none of them are very happy: 1) quit, 2) aged out, 3) injured.
Of course, a great coach for one kid is not always a great coach for another kid. I think some truly amazing coaches are the ones who can adapt their style to many different types of gymnasts and personalities. Different gyms have different attitudes towards this...some pick kids for team who fit with the "type" the coach works well with. Others accept all kids for team who have certain skills and work ethic.
Also - "top coaches", or the coaches who work with the Level 10s or the elite track - they're not always good at coaching lower levels/less talented kids. Lots of people work best with a certain level, and it's often not the upper ones. Most coaches also have certain events they're better at or like more than others, just like gymnasts.
There's currently a new coach at my gym who has an incredibly impressive resume at the top levels, and hosted a workshop for all the gym's coaches. The man does not know how to teach a cartwheel. He's never had to teach a cartwheel. Yet, teaching good cartwheels from scratch is one of the biggest challenges and most satisfying accomplishments for our beginning rec coaches and gymnasts.