But here's a reality check of a different kind. Work with a good BJJ practitioner, or a good Wing Chun person, or several arts - or a boxer who has been hit a thousand times - and see how far your atemi gets you, or what the ultimate results are.
Well, this is somewhat my point... all of these guys know how to strike. When they fight they are careful about being hit because the consequence of taking a hit from someone who can strike can be a fight ender. They have to put attention on making sure they aren't open, not just charge in and attack your openings. That "attention" can be used to effect their minds and this effects their bodies.
This whole thing of "taking punches" is about sport. In any kind of competition, none of these people are striking to kill or disable. It would be quite a bit different if strikes were to the eyes or throat... a good wing chun practitioner could kill you with a punch to the heart. The fact that most Aikdo people can't strike very well isn't the fault of the art, it's the fault of the training.
Look at Shioda Sensei's encounter in Shanghai during the war. He and a buddy were cornered in a bar by some Chinese gang members. I have no doubt that they intended to kill Shioda and his friend; this wasn't just a bar brawl. The first guy through the door got a broken bottle to his face, the second guy through the door threw a kick and Shioda broke his leg. The potential to do that is at the heart of what we do; we make a conscious choice not to, to create something creative rather than destructive, but it is there.
The fact is that O-Sensei created Aikido to be something more than that. I don't believe that Aikido is really about fighting at all. It's about perfecting yourself. It is about losing the fear that creates aggression in all of us. I almost never hit anyone when I am training... but they better remember that the strikes are always there or they get a reminder in the form of a gentle tap. I have never seen any effective Aikido where this wasn't the case. We just had Endo Sensei here in Seattle and even he periodically had to adjust people's structure by showing them that they were open with atemi. His is some of the most beautiful and soft waza you'd ever feel and he has virtually no interest in fighting at all. But if you broke your posture and stuck a nose in where it should be, he'd readjust your mistaken form by showing where the opening was for the strike. It is simply inherent in what we do.
If you take the atemi out of Aikido there is no Budo. It's just a dance. With no atemi, no one understands openings, no one has to worry about proper structure, no one understands about proper spacing, one can totally resist technique in the dumbest ways because there is no consequence.