How do you feel it is affecting the progress of his students?
I've very glad to see Aikidoka opening up to the idea that other arts have knowledge that can help enrich our Aikido practice and learning.
The reception of that knowledge is a tricky thing. I think you have to have a lot of trust in your teacher, especially when you're used to doing things in the traditional manner. Ikeda sensei's personality and the way he lives his life makes it easy for me to trust him when he says that something has merit. Especially with his avoidance of mysticism, for him to praise the internal work said to me that it was something that I should take seriously. But then if he said to jump in a lake, I'd probably kick my shoes off and go for it with the feeling that he has a good reason for telling me to. I don't blindly believe and follow everything I'm told, but I'll at least make the effort to explore for myself. His endorsement of Systema played a large part in me getting into it, and that's hugely benefited my Aikido.
I don't think everyone is as accepting of a teacher's direction, and with the internal work especially I think it's difficult. With his traditional kuzushi work an outsider might not see that the uke was affected, but the uke could feel it. With the internal work not even the uke can feel that anything has changed. Ushiro sensei's work at the summer camps was received by some people with "they're just tricks" and other forms of skepticism, sometimes even after people got to experience it personally.
My experience has been that change is hard for people, and especially things that they can't fully explain. What I see is that more of the resistance to the internal work is in the yudansha than the beginners and that it'll take some time for it to become a normal part of practice.
George talked a little about the issue of integrating internal work with our established testing and promotion curriculum. I'm trying to reconcile how to put all the pieces together. One the one hand I need to make sure my students fulfill their testing requirements and get the proper technical kihon skills. At the same time I'd prefer to start someone with much more breath, relaxation, and internal work. I feel like the kihon focus by itself actually instills a lot of tension and other habits that are difficult to break later.
On top of that you need to keep people showing up and for a beginner the internal work might not have as much of a "wow fun" factor that will keep them going past the first few months. I'm sad to admit that when potential students are watching a class that I'll avoid doing much internal work in it; I know it's just not exciting to watch people stand around doing what looks like nothing. So from that end it seems like something that, while it would benefit every level of student, maybe only the advanced or truly dedicated student would appreciate studying in any depth.
Loosing students and rewriting the curriculum aren't things that I'm ready for right now, so I'll keep trying to fit the internal work in as I can.
I think what you'd notice the most in my students from the internal work is that their ukemi is different. The first few years that I was teaching ukemi seminars I was doing a lot of the soft "feather" type high falls. The last couple years of seminars have focused more on internal work, how to take the power of a throw and transform it internally in a way that doesn't require slapping, crashing into the mat, or even "feather" gymnastics. You throw them hard and they just quietly sink to the mat. I believe that this feel will ultimately carry over to the throwing side for them.