There's some truth to that David but again as Stefan pointed out Shoji Nishio and his senior Yudansha were not big....He was rather modest in stature even for a Japanese person. He handled me and everything I could throw at him with ease and I am 6'2" 250. So I had to be at least 70 or 80 pounds heavier.
When I share the mat with anyone big or small I show them how to "cut" and "lead" Uke never "push" just the way my Sensei does it.
I do agree that pushing in most cases is the lazy Nage's way to make a technique look "good/real".
Yes, I can't think of one example I've ever seen where Nishio Sensei looked similar to what we see in the other video or even where what he was doing might have been considered a historical source for what we are seeing in the other video. Yes, I totally agree with you - with Nishio Sensei, we are looking at something else.
To be more clear, and not referring to the skill set of the practitioner at all, I do believe that Aikido architectures are constructed to handle folks bigger than nage. My comment about lighter/thinner attacker training environments regards ONLY what I'm referring to as a "current trend" to push. When you look at that current trend to push structurally, again not referring to the skill set of the practitioner, it's obvious that it is assuming that nage's mass is either greater or equal to that of uke's - regardless of how much uke's center was already taken. If one would follow my logic out, you'd find that, yes, I do not see that pushing as Aikido.
If folks want to push, they should push that trend and its associated champions out of that part of their imagination that they use to inspire and motivate themselves - i.e. they should find new models, new examples (like a Nishio Sensei, etc.). They should guide their training by different stars. Folks should be critical of the pushing, and not so fast to defend it or it's champions. That's my take on things.