When I trained with Nariyama-shihan last week at the World Championship he commented on all atemi waza. I think that it was Sakai-sensei doing the translation and I am not sure how accurate it was. It was during one of his three seminars he gave.
He said that the hand needs to be placed WITHOUT hitting uke. If you are not capable of doing all atemi techniques with a soft placement of the hand, then you are not worthy of doing randori. I am not sure how strong those words were as my Japanese is not good enough to understand him but that was the gist of it.
So, yes they look really hard but they are not if done properly. It's all kuzushi, or it should be all kuzushi.
BTW, Peter were you there?