I was told that including atemi (strike) at the conclusion of an aikido technique was generally viewed a improper traditionally during practice. I can understand why this might be the case coming from the philosophic basis of aikido in general.
Seemed O-Sensei seems to have been a fan of using atemi to finish Irimi Nage, if nothing else: http://youtu.be/zkRbVdmTmIA?t=6m
. Given that this video was made relatively late in his life, this would indicate that atemi wasn't relegated to Ueshiba's Daito-ryu or other pre-war teaching.