A quick addition to the "soft" concept- it may look "bouncy" or not, that is up to the individual. I've been thrown by Ki Society members and the last thing you can come up with in that moment, is that it was "soft"
....in a way it was, But also very decisive and effective.
Soft in the Ki Society is a lead to be "calm & relaxed", in order to execute a technic in an efficient and non-harming manner
What you have in Steve Nelson's video link is one (of 30) Taigi arts. That's a different issue, that emphasizes rhythm timing and harmony, all done "soft" using a sequence of Aikido arts. See also
http://toitsu.de/video/video.htm