In chatting with Roy, at that point I hadn't yet started taking drumming lessons, but I was thinking about it, and I brought that up. Roy's advice to me was, "don't find someone who's going to tell you how to play, find a teacher who is going to teach you how to practice." His belief was that becoming an instrumentalist is more about fine tuning your personal approach to how YOU do it. So many teachers try to shoehorn their students into their own personal approach, and while there are generalities that work for the majority, knowing how to practice and why you are working on the various things you work on is also key to your development.
At the end of the day a good teacher merely points out flaws you may not have noticed, and streamlines your approach by keeping you on a more narrow path toward your end goals. All of the rest of it is the work put in by the student themselves.