The support for the platform would have to be quite different to facilitate lifting it with just your feet (in order to make the most of your height per move) and to not wear out your core fighting friction and the saddle.I'm all for it. Finally!
Do you know what mods they're going to make the top to facilitate this?
As is, it appears you can't "herringbone" feet under the arms of the top portion unless your feet are very flat. And will the cable adjustment be manageable, in your opinion, while climbing to account for tree taper?
The saddle is squeezing your legs together and constricting your glutes which provide the greatest power in the first part of the "squat" going up, while at the same time your legs want to bow out because the tree blocks your knees going upwards and forward.
A soft 2 foot loop allows your feet and legs to angle outwards but a flat stiff platform restricts that and puts all the stress on your quads which can tire most people out since they're such a large muscle.
You're also right abt tree taper being a major challenge.