Hey Joe, there is a pivotal point on the heel. Not the heel pad, but an actual point. I like the term pivotal point - because it demonstrates that point as a "drain." If was tried to turn on our heel pads...we'd just get mush...and most likely just get stuck and stop. The energy would not drain down faster than it's rising in the heel. But with a point - it drains the energy - which creates power - directed, transformed energy.
Plus, look at Ueshiba's heels at :40 Nuff said. https://www.youtube.com/watch?v=XoDK3XuvZWw
Also notice he uses a single point on the outside of the ball on his left foot.
Here's the difference of turning on the heel pad vs turning on a point: The heel when pressed into the pad, actually couples the heel with the leg and the energy in the leg. The energy is not used. Contrast that with moving the energy to as, as you call it, the "pivotal point" - that point - decouples the heel from the leg - and that point creates a vortex drain for the energy - transforming the energy into power. And in fact, it's that point that is the lead for the power.
I can tell you there is heel work in aikido - even if the movements are very small. Aikido is more Chinese than you might think. It may not be taught at the level of "shu" in most of the schools, but by the time you get to "ha" and certainly "ri" and start truly creating your own aikido, everything has to be examined, and nothing can be ruled out.
Also, the need to Create the Disc is going to have people moving in ways they may not have done in their formal training in aikido classes. Most aikidoists really have no clue how to move like that. Most people training and teaching aikido aren't doing aikido. But people are waking up.
Thanks for jumping in and giving me something to chew on towards tweaking the presentation. Cheers...