It does not matter how good your techniques are, if you have no spirit you can do nothing. Some would say without spirit there is no life, some.
Not the ones that would have been used by trained judoka like Mochizuki and Shioda to attack O'Sensei, and not the ones we use in Yoseikan. If you are limiting the technical scope of Aikido, it is not Aikido.
I would agree that it is a little more developed then some judo Ne-Waza, but just from the point of view of self defence. Look at Kosen Judo (high school Judo) were the majority of training is done on the ground for safety purposes.
But the point is he defeated his attackers with the "simple" techniques he was learning from Daito Ryu. This is how Mochizuki Kancho described it! O'Sensei would learn from Takeda, who would only teach him. Then when he left, O'Sensei would call the others back into the dojo and basically say "attack me." From here O'Sensei would use what he had just learnt to defeat all of them. Then when he was finished, the students got a chance to try against each other. No teaching, just training!
My joke is still intended to contain the serious message. Many students who attacked O'Sensei state that it was like he knew how they would attack. One even tried to deceive him by changing his attack, and O'Sensei said, "that won't work either," before he had even attacked. If a man like Mochizuki Kancho recalls stories like this, I can do nothing but believe they were true.
I study Aikido and I study "fast knockouts via blows to the chin." Again limiting the techniques of Aikido means that it is not Aikido
His small amount of training is both Sumo and Judo would have contributed to his overall martial development, but this does not mean he was a grappler. Takeda only studied Daito Ryu (or whatever it was called back then). Takeda easily overcame O'Sensei when he was challenged him.
I have to ask, although I agree a hard knock out punch will knock you out, how are you training that punch? When I train I focus on proper head movement, and strikes to setup my takedowns (its' a fight not a bjj match). So are you training to deal with trained strikers closing the distance to a clinch?
I personally never recommend the one punch one kill approach. I've been hit very hard with no effect, I've been grazed and knocked on my butt. It's not reliable. This is why the UFC calls it a punchers chance.