Mark - I've only seen it from afar, so to speak. It looks very intelligent. I've seen guys roll - really mold their bodies - over projecting surfaces, for example. Systema (and other related Russian arts) brings to my mind moving like an octopus - an alive connection throughout the body without a focus on hara at all. I think if one regards ukemi as primarily falling, Systema style is better and safer than aikido. If ukemi, however, is "receiving body," and includes kaeshiwaza, and the use of one's own physical organization to dominate the other (turning tori into uke), there may be some divergences in goal and effect.
My question would be this: (and for me, it would bring the question into internal strength/aiki questions, where, too much digression should start another thread). Ukemi is "of a piece" with the rest of a martial art. If one takes ukemi like they do in systema (and ukemi, of course, not merely being falling), what would that do to a) aikido waza b) would that contribute to training a the particular type of "inter-connections" to move and execute the aiki/kokyu ryoku that O-sensei exhibited, and some others are looking for?
This is not a criticism of Systema - rather, to my eyes, they are developing their bodies in a different way. At "lower" levels, this is not an issue - adding some whip and flexibility to one's body in aikido would only be a plus. However, I think that when one gets to an expert level, it is possible that it would be the equivalent to trying to run your computer simultaneously on two operating systems.
Just my opinion - I've only taken a one week Systema training.
You raise some very good points. The expo had a profound impact on all aspects of my budo training; ukemi being one aspect as part of an integrated whole. Your ukemi dvd is in my collection and has been part of my re-analysis process. My blog on ukemi (my dojo website) talks about similar thoughts on the whole area of ukemi. One of the things that I took from Systema was in allowing the laws of physics and other laws of nature to be more important that the desire to make my "roll" look nice.
Do you remember Ushiro Sensei's son? He has matured into quite the beast! We had not seen each other in 8 years (couple of years ago) and he put on 25 kilos of muscle during those years. He and I went at it during a break (we would lock ourselves in a room and go at each other at the expo- not everybody's idea of fun and comraderie, but we loved it!). We were going full-tilt, throws, sacrifice throws, etc. on a hard wood floor. We both walked away from that fun encounter with no bruises. It was confirmation for me that the traditional ukemi model employs, that I moved away from was a good decision. I wish I was more coherent in thinking through what I am doing differently now. I sum it up by saying that I can receive energy in a number of ways, enabling me to do a variety of things as a result of receiving the energy. Much better than launching into a roll (in my opinion). Watching and experiencing what Systema does, along with your DVD, were part of the changes which I consider positive. Thank you for that dvd.
As to the question of what two IP people would look like testing each other, I think that Chinese wrestling and boxing would be closer to what it would look like. Eventually, one operating system would be left running. In terms of Aikido waza, I think that it would be like when kata evolves into movements done during kumite. My experience is that it typically ends up looking very different than how a cooperative waza practice looks. I do not necessarily look at this as a bad thing, just something that is likely to occur. I also think that it is important to be able to learn to use the internal form contained in the external form of waza, without being constrained by the external form.