Actually, the kotegaeshi broke the guy's balance to the point where he was heading to the asphalt. The reason he got to save his hand was because I had no intention of bouncing him off the asphalt to begin with. I merely used him as a shield against his pals. I left him the option to disengage and he took it. I had no idea if the guy was drunk and just playing the a$$ with me as is also the norm during the time when he attacked.
The same guy got the shomen ate before he reached for me and got the kotegaeshi. He initiated the attack by trying to shove me into his pals and get me on the ground. The shomen ate was more of a throw/push against the face than a percussive atemi (which is usually how we use it). Tai sabaki is what caused his shove to fail, not atemi, all that did was make him realise that I would not stand for it, but he failed to listen the first time.
So I guess you misunderstood my original post. Also, this thread does not necessarily have to do with outside the dojo effectiveness, I'm talking about effectiveness anywhere. It could be inside the dojo during resistance training for example.
As far as chances of having poor footwork etc. it depends on what your focus of training is in. If one trains these things to be reliable in certain situations the likelihood of it failing is severely lessened. Hell, it worked for me.
In reflecting on the encounter, correct footwork and ma ai control is exactly what helped me to survive, else I would have ended up on the ground and gotten kicked into oblivion like another unlucky person that day. The technique imo was very secondary.
Just my thoughts.