"I believe it's got to be a blend of the two. I've had old-school teachers who thought students had to 'steal' the art, and would even teach things incorrectly here and there just to keep their secrets."
Perhaps rather than being a blend, we should teach in the way we are personally most effective. Some people don't have the background to analyse the physics, some do. It is probably important to know which you are.
I'm sure all teachers have been asked which foot to put forwards and had to go through the motions to answer the question, so performance is also important. But some excellent performers just don't know how to teach. OTOH, if you don't have the information, it doesn't matter how good a teacher you are.