Post #6 is quite a bit to digest.
It'll take me awhile to do that, but I found in a quick overview that everything you posted seemed like good, sound advice to me. Well worth thinking about.
I like the tier down approach because what the shihan is working on is most likely not going to be understood by beginners all that well. However, the top students would benefit greatly. Then, those students will work with the next tier, etc. And it would work in small groups, too, which is another benefit.
And I found myself nodding in agreement with your #4 about large seminars not having any benefit. I've found that smaller seminars have a more focused training environment and actually end up adding more zest/vigor/vim/etc to the attendees outlook and training. But doing away with the large seminars means more smaller seminars and that takes up more time. Is it something that the upper ranks and shihan can, or will, do? I really don't know.
I'll keep the information in my mind as I progress through my training and maybe one day I'll be in a position to help implement some of it. Until then, you've given some very good posts to digest and to think about for some time.