I haven't attended the seminar but instaed I know:
You can find everything you did in that two hour class on one of the three basic DVDs (one of them shows his kihon waza) and on one of his Seminar DVDs.
With explanations, preparatory exercises, alternatives, ways to techniques, showing common mistakes or difficulties and and and.
One of the things his scholars like is his precices and efficient way of teaching.
Shouldn't call it aikido anymore ...?
Do you know Endo's technique, his kihon waza?
Have you ever seen a dan-examination held by Endo?
May I ask which style of Aikido you are doing?
I see you are one of ‘believers'. One of those, who during seminars, sit around and admire Endo sensei beautiful technique and how well he applies very sophisticated principles?
See, me, I'm not sitting during seminars. I'm not learning from books, DVD or from talks. I'm using all this time for purely physical practice. And you know what I learned? You can't teach beginners very sophisticated elements. Even if these elements are ‘the essence' of aikido. There were many other instructors, not only Yamaguchi and Endo sensei that were trying to teach only ‘essence' to beginners i.e. Hirokazu Kobayashi, Nakazono sensei, K.Tohei…etc…
I had many opportunities to practice with students of those instructors during all these years, and see the result of their teaching. In all cases
, those who didn't have very solid basic training, were not able to apply even roughly a single one of those sophisticated details with someone who was not very familiar with their style. I'm talking here about normal, friendly practice, not any kaeshi waza training.
Those, who practice only ‘essence' didn't understand at all martial principles i.e. correct distance, because nobody ever hit them strongly in the head or in the stomach with the hand, foot or a weapon….What it worst, they always blamed uke for the failure of their techniques. So they will never develop misogi training. And will not reach a goal of aikido.
As you see, the weakness here is not a particular aikido style, or instructor, but the way of teaching. Don't feel offended personally by my writing, I really have very wide experience with different aikido styles, so I can compare and see the strong points but also the weaknesses.