I think Mert is trying to get you to think about what you'd do in the instance shown in the video he posted, which is an application of Hakkoryu's niho nage as taught in the past and still described by Shodai Soke Okuyama in the higishi manuals today. Realize this is an exercise, like waza, but it has a point to teach.
Even if the receiver has traction on the floor, the movement to upset him is the important point, and to be able to do this with relaxation is key. This isn't the technique that best demonstrates "aiki" in my opinion but I can understand why he chose it.
Mert, please let me know if we're on the same page in this regard.
Yes, that's what I was going after. What works in this variation of Niho Nage is the same thing that must be present for the very first technique in the syllabus, and all others thereafter, to work; and so it's foundational to aiki vs. being a grand exposition of aiki.
But the wall is there to set parameters: the tori has to get really low -- so yes, that's a prerequisite for any interpretation of the technique -- but the tori's body can't leave the wall, he can't physically lower his posture to get leverage, and yet he must relax. This is a challenge whether the uke is wearing socks or not, and whether the tori is relaxed or not. If someone hasn't tried it, perhaps give it a go.