I'm also doing Aikido for about 15 years now and I am teaching on an regular base for 3,5 years. I am one of four teachers in our Dojo.
Often times I have these grand ideas tying techniques together or every once in a while I'll have some philosophical idea that can be explained through Aikido movement etc.
I teach the main advanced class and I myself learn a lot by teaching my - what you call - "grand ideas".
And this way of teaching is highly appreciated by the students very much.
We all together get a lot out of it.
Then I get into class and realize that half of the students are just learning how to fall. More often than not my wonderful ideas get thrown out the window and I change my class to adapt to the students
Because of that we have structured our classes: So we have beginners (2 per week), basics (2 per week) and advanced (2 per week) classes.
Basics and beginner is sometimes not strictly separated. But to take part in the advanced classes you have to be abel at least to do frontrolls. So everyone can take ukemi and can practice with the others.
Since I do Aikido there has always been this structure of practice. Everybody knows what to expect in a class. And everyone can choose where to take part.
And because the seniors always take part in the beginners training and the basic Training is suitable for both groups, there is only a distinction of topics of the classes and not a separation of the members of the dojo.
I'm curious... those of you that have been teaching for a long time, if you had the students ready to learn what you had to offer...what is it that you really want to teach?
When I started to teach, I simply tried to teach what I was taught by my then teacher.
In the meantime some things happened: New teacher too far away to see him every month; nidan grading and intensiv preparation before that over one year; I got to know the Aikido of Endo Sensei ...
My Aikido changed and developed. I found a lot.
Now I try to teach the things I found on my way with my teacher and with our shihan, the things which are important to me. I wouldn't call It grand Ideas but "my understanding of ..."