We belong to a small dojo -- only 3 of ours in the U.S. -- affiliated with Aikikai, and any seminar we go to is inevitably outside our "style" (Kodokan Aikido).
These have included seminars with the late Saito Shihan, Pat Hendricks Sensei, Ikeda and Saetome Shihans, and the esteemed Aviv Sensei (though I seem to have missed out on that last friendship seminar due to my schedule).
All of these have added to my own individual technique, and the opportunity I had to study Iwama weapons for a couple of years on a regular basis helped my understanding of body movement tremendously.
I think it's all fine if Hitohiro Sensei leaves the Aikikai; I just hope that all of his students retain the openness of training with non-Iwama students that I have so enjoyed in the past.
PS -- Hope to train with you again soon Aviv, though I'll be in Chicago during your upcoming seminar