Josh and others,
Two quick thoughts as I watched the video clip and read the posts in this thread...
1) Judging from Ikeda Sensei's appearance in the video (I've been going to his seminars for 20+ years), I would say that the event filmed was not recent but a number of years ago, quite possibly before 2005/2006. That is important because Ikeda Sensei didn't encounter Ushiro Sensei until 2005, and he has commented several times that meeting Ushiro Sensei and participating in his classes gave him a new language/conceptual framework for what he was working on in his own aikido.
2) My own observation of Ikeda Sensei's teaching over the time I have known him is that his use of language changes as he keeps exploring a theme for a period of several years. So what he says during a seminar now is different and often clearer/closer to the mark than what he was saying back in 2007 or 2008 when his seminars underwent a significant shift to the IS/IP perspective.
So the answer to your question and others related to it may lie, in part, in placing this particular video clip in the context of when it was filmed.
My $0.02, for what they are worth...
Excellent points, and to take them further, I've been contacted via PM by someone who wishes to remain anonymous but who was at that particular seminar, which was in 2000. They have given me permission to paraphrase their PM to use in this post.
The theme of the seminar was, in fact, how to change the angle at the point of contact to weaken the uke's upper body by either rotating (i.e. supinating and pronating) your forearm or by bending your elbow to disengage their shoulder. The point of this particular clip, from what they remember, was to then use that tactic (which was explicitly practiced right before the clip takes place) to move uke, using the whole body.
So this is now an even better illustration of the dangers of using out-of-context video clips; even though I was correct in my technical analysis of what he was physically doing, I was wrong about what he was trying to get across because I heard "use your whole body" in isolation from everything that went on for hours or days leading up to that moment, so both Phi and I misunderstood what point he was trying to make.
Also excellent points, but that is opening up a can of worms that probably deserves its own topic. Or its own dissertation. Thanks for adding to the thread.