As a teacher moves up the ranks he/she has a responsibility for improving the craft of teaching within themselves. Teachers that teach principles rather than techniques are more skilled seminar teachers.
It is my firm belief that once a teacher becomes of advanced rank and they start teaching seminars they need to improve their skill at teaching. As I have written before, I really dislike going to a seminar and having a poorly constructed lesson. Please great teachers do not merely run me through the basic techniques of your system. An advanced teacher teaches principles so we understand the hows and whys of a technique. I no longer want to merely copy a great teacher's aikido. I want the principles to make my aikido develop.
Once a teacher becomes a seminar level teacher they should stop teaching techniques and basic kata. First of all going through the process of learning kata is what regular class is for. Second, if I do not already know the collection of techniques, likely I will not use them in my practice anyhow.
Of course the advanced teacher can and should use a kata, or collection of techniques to teach the deeper principles. For example, "let's look at breathing in techniques and lets use the atemi waza kata to explore that idea." The advanced teacher needs to narrow down an element of budo and help the student see it in all levels of his practice.
In my humble opinion a good seminar teacher is a principles teacher. A good seminar teachers transcends the limitations of a single art form and enlightens the student to the nature of all martial forms.