This may be off topic. But is there any proof that training with Ueshiba helped them in any way? Did they eventually win against Ueshiba? If not, how do you really know that training with him helped?
Lets break it down.
1) I'm a bad ass
2) I get my ass kicked by a bigger bad ass
3) I train with said bigger bad ass
4) Now we assume that training with said bad ass makes me even more bad ass?
This seems to have the assumption that just because a guy is awesome at fighting he is awesome at teaching. And thus would improve your ability to fight. We simply assume that training with Ueshiba helped him in (in terms of fighting) ways that training in other martial arts did not.
As for how his students progressed ...
There are some reports where Tomiki did things that Ueshiba could do. One is where he held out his hand and had judo people try to throw him and they couldn't.
Another is the training session with Shioda where Ueshiba tested him with bokken and empty hand. He passed in one and was not as good with the other. And don't forget the stories about Shioda going outside the dojo and testing his training in bar fights.
There is the stories about Tenryu training a short time and Ueshiba telling him he is done.
So, in one manner, yeah, Ueshiba (at least in some instances) trained some people to a decent level. Since he (Ueshiba) had already been training before his students started, I doubt that they would have surpassed him until he was old. By then, well ... as Ellis Amdur posted recently about Kuroiwa sensei ...
Ellis Amdur wrote:
Kuroiwa sensei smiled -- "You can't knock your teacher over when your teacher just announces in front of an audience that you can't knock him over."
Going back on topic, Ueshiba did things in his training that don't seem to be done currently. And if they are, they are so watered down (push tests for example), that they are but a shell of the real thing. Why?