Re: Randori, Sempai and experiences
I'm not inclined to trust much film of Ueshiba showing aikido. Film perforce is a demonstration (whether an official embu or not) and I highly doubt his uke were ever going to allow Ueshiba to look anything less than perfect on film.
There is, however, footage of Ueshiba applying shiho-nage to U.S. servicemen. This is very instructive because unlike Ueshiba's uke (who fall in the same footage as cleanly as usual), the servicemen are not practiced in aikido ukemi, nor inclined to give in to the old man. Ueshiba's technique works. It's not pretty, but the men do go down, and by entirely recognizable shiho-nage.
So, IMO, the uke in any footage of Ueshiba is focusing on clean ukemi, not on providing Ueshiba with a typical training partner. And given that a number of Ueshiba's direct students (Saito, Shioda, Abbe, to name a few) have taught their students to provide solid resistence as uke, I think that's even more indicative of how aikido was truly trained, rather than demonstrated.