Best Aikido the Masters Course or Best Aikido, I'm not sure which (don't have it in front of me) defines atemi as strikes to vital points (pressure points). If anyone took some of the atemi out (at least in his books) it would be nidai doshu in my opinion. I don't recall Aikido showing one atemi strike and only mentioning it briefly. Yet, the new books show atemi regularly and discuss it as well. Although we may all aspire to O'Sensei's level, we lowly students may have to rely on atemi.
Most of what I've heard is so far word of mouth which changes with time in most cases.