I never even considered that some coaches are not a good fit, my daughter was in a mixed aged development group for a year and made progress in gymnastics but not as much as she could have, some of the problem was social and some was due to coaching style now I look back on it.
My daughter has just started a new group with more hours and an extra day, there are 7 girls in the group and two coaches, these coaches are more hands on especially when conditioning, in pull ups there has been a big improvememt, instead of being left to struggle on their own they now have help if they cannot do it in their own.
The differences in coaching styles had an effect on my young daughter, she has gone from being slightly withdrawn in the gym, on the outside and hanging back avoiding the coach, to a bouncy happy child full of energy , I know it is early days but I hope this continues. My daughter loved her old coach but admitted that she was not happy or comfortable in her old group, that might be due to my daughters personality of suspected condition (suspected Apsergers / Autism).
Also it doesn't pay for a coach to be a yeller in our gym this can cause you to get suspended if you doing it in a mean way instead of just shouting to make your self heard in a noisy gym.