The man basically committed most of his time and energy to training in Japanese martial arts. Even if he had no talent at all, he was bound to be an excellent martial artist.
Now add talent, a lot of perseverance and dedication, and you have one of the truly great ones. Then he unselfishly taught his art to many others and we all get to practice aikido today because of it.
Excuse me for having the highest respect and regard for O-Sensei, but I think he deserves it.
If some egocentric pig feels he's qualified to judge O-Sensei, then I pray he never crosses my path. Respect is the foundation of the martial arts, especially for the founder of one's art. If one doesn't have that, then one doesn't have anything, and I'll drink no beer with you.
(Sorry for the harshness here, but I've seen this line of reasoning on other threads, usually by DR people, and it REALLY pisses me off!)