I think it is a good clip and provides a different way at looking at Aikido effectiveness, that has been discussed lately, against common street attacks where the attacker is unaware of the Aikido trained target. The attacks seen in the clip represent 99.9% of what will be experience in the street in most places in the world. The clip doesn't show all the common attacks someone might experience, but they are the major ones -the clip gets you the idea.
I really liked that video as a demonstration. It's one of the better demo's I've seen online...for the use of speed and ukemi somewhere other than a mat. It also showed some variety so all in all a good video in my view. I particularly liked the use of atemi in some of the movements.
As for your thread's question, I think the point Dan made about taking ukemi is the main reason it might not be described as an example of something "effective" or "realistic." My very limited experience is that many people will simply fall down or do "bad" movements which change the nature of nage's movement. In other words it's stylized because all the people in the video probably practice the same stuff together. Then again video representations always fall short. Even Kevin's video, where they're supposed to be able to go all out (more or less), it seemed to me the attacker stopped attacking. That doesn't mean it's not effective per se, just that I as a casual observer was able to see a moment where the attacker might simply have been processing what to do next (or even allowing nage to find his way in) instead of following through with another attack...and that happens often enough in Real Life.