Well historically shihonage has been the most destructive technique. Gotta to love the Shihonage Sabu Chan stories!
Actually, I read a study in the past(it might of been in one of the old-old-old paper versions of Aikido Journal, not remembering now.) but it actually said shihonage had the worse track record for injuries. Iriminage was also really bad. But techniques like koshi and jujinage were relatively low for injuries.(I'd like to point out that they included university clubs in the study. They attributed injuries at these clubs to poor instruction, and a lack of high ranking students to administer classes...so basically a bunch of 19 year old guys messing around and accidentally hurting each other.)