Thanks so much for your explanation. I downloaded the appropriate software and so was able to view the videos. That plus your commentary have inspired a lot of thought and I am now thinking of how to incorporate stuff.
A couple of comments,
I understand that any negative reaction during such drills is likely due to a number of causes. One of which is likely to be not feeling safe (psychologically) with one's training partners. I think that there needs to be a kind of "We are all in this together, helping each other" attitude before one can relax into or trust in the drills to do their work. I think the best way to do this is a lot of cooperative kata training. If we define "kata" as fixed role-playing of a combative situation as opposed to "drill" which might be defined as unfixed or semi-fixed role-playing of a combative situation, kata is obviously less psychologically demanding. People new to martial arts or Aikido can start to find their bearings in this weird world of strange movements, customs, clothing, and language if everything is fixed. It is my experience that two beginners are much more likely to become friends than a newer person and a more experienced person. That is because they both see the other struggling just like themselves and that helps them form a bond. To me, this is the most important thing about beginning aikido.
I think that it is between two people who have formed a close relationship that drills can have the most positive effect. They can safely (psychologically) push each other. The point is not to test but to explore. When we are tested, we revert to what we already know. That is why I feel that a person should not be pushed too much during drills nor kata. And the less one is pushed psychologically the more they can be pushed physically, and vice versa. I think that the adrenal dump type training that is now the rage is for 1. to show the person their current reality and 2. how to work within those new-found parameters. I think that arts like Aikido and systema are different. Here, the main point is to expand what an individual is capable of. That is, adrenal training is testing and working with the results, Aikido is expanding capabilities.
I always read with chagrin posts which say that aikido is not effective because there is no resistance. This, in my opinion, is false. Resistance naturally happens when two members of a dojo start to trust and respect each other. I have done similar training as the drills on David's website. However, they were always informal and all of a sudden. One friend just suddenly starts to pour it on until both are on the ground and one person is pinned. Then both laugh and stand up to go on to the next technique. I do think that David's drills are a very good idea and I would probably greatly improve if I made my "free" training a little more structured.
Of course, this is just my current thinking and as always, I reserve the right to be wrong.