My general opinion is that with many demonstrations uke is working too hard to make tori look good.
In the entrying videos you can see a uke, who is bothering to follow toris movement and to hold the contact in a very limber way, not everybody is able to do it like this. So his reaction is one part due to his flexibility. On the other Hand he is is well-rehearsed to the movements of his teacher, so there will be no real surprising actions for him.
If uke is compliant in this special way, tori can do things that make the demonstration look like it does, but to move uke in this way with little or no effort is also not so easy as it looks like.
Its just a kind of practice that helps to achieve body skills, not a demonstration of magical power.
Wheather tori could do it in the same way with a stiff and uncompliant uke, is not really important, of course he couldn't. Maybe he would impress uke in some way, but it certainly wouldn't look like it does in the video.
It is not easy to compare this with the tomiki-video, but in this one tori has to deal with real attacking force, whereas in the first Videos uke does nothing than react to toris movements.