Re: Sensei role!
Well, A few things. When a teacher stops learning decades ago (as you put it), is he stimulating you at any way?
As I see it: the basics are most importantand should be practised several years under the guidance of a capable teacher.
After becoming a yudansha there is the matter of color. I don't like the word style. We are divided enough don't you agree?
Visiting other teachers on seminars (I started very early with this) gives you other viewpoints and this can be taken into your own practise if it fits you. I allways think about a seminar after a few month to see what is still in my mind or body. (no particular order). If nothing is there, I go on. If something is there I try to figure out what it is and what it means to me.
I hope that my teacher allows this kind of development. If not, (s)he is not right for me. It holds you back.