Re: Why bother keeping Aikido 'pure'?
Ueshiba did sumo and other hard styles of martial arts and tons of physical conditioning including strength training with railway ties. He also got into a lot of physical encounters to practice his arts.
This is something that is lacking in the vast majority of Aikido practitioners. To say all of this had nothing to do with the effectiveness he demonstrated and that it was his spiritual awaking later on that made him effective is quite absurd.
I remember a video being posted here many years ago of a 300lb+ person going into a rampage in a store and everyone here was wondering how they could possibly deal with someone like that with their Aikido. The answer is quite clear, get strong! If you can squat 400+ pounds and deadlift 500+ pounds, doing a single leg takedown, or a variation of koshinage, of a guy that big would be pretty easy actually.
Aikido does not focus on using strength but being strong is still a large part of the puzzle. It is much easier to put someone down on the ground if you are stronger than them, even using Aikido.
100% pure Aikido is not enough, it wasn't for the founder, he was freakishly strong and studied a variety of style including wrestling.