Actually Cady there's a lot that can be gleaned by just watching someone move.....
The highest level Aikido senseis I have had hands on experience with (S. Maruyama, S. Imaizumi and the late K. Toyoda) have all demonstrated what you would call IP/IS to a high degree. I know for a fact that Maruyama never went "outside" Aikido and surmise that Imaizumi and Toyoda both stayed within the fold also (tho' I'm open to correction there).
If that's so, I feel they must in a way have had surpassed Tohei in this respect or the way you see IP/IS is somehow different from what I think Chris Li has pointed out via his translations. Tohei seemed to me not too different from very good technicians, admittedly very strong and always very relaxed. No "weird" power. Rather the epitome of natural movement....
Can't pin it down in words better and of course I might be wrong.