I gotta say I agree with this completely. Moreover, I would not interpret a small client base as a measure of a coach’s ability, but rather a reflection of how little money most yoyoers have to throw at the problem.
Besides, given how little regard education gets from people in general, it isn’t hard to see how most yoyoers would rather put their money towards new yoyos (toys, yay!) rather than learning/training (sounds like work, boo!), especially since the Internet has made learning tricks largely cost-free today.
However, I feel that this is a potentially invaluable service, and I can foresee a point in the not-too-distant future when I will be taking Andy up on it, assuming he is still offering it then.