I have to disagree about some things said about ikkyo and shihonage though. First of all, how does ikkyo injure joints. I have been brought down hard with ikkyo, my nose into the mat, but I can't remember it ever hurting my joints. I've also never had shihonage hurt my shoulder, you can do it and break an arm at the elbow but if you bring the arm around quickly and bring the hand behind the shoulder blade, you can drop a person on his back rather quickly without putting much pressure on his joints. I also think ikkyo is one of the easiest techniques to do at high speeds, but maybe that's because I practiced it so much for my fifth kyu exam (from a shomen uchi attack).
At high speeds you will often see someone high fall with shiho nage. The danger isn't so much in doing things right but in doing them not quite so right. In randori you will have a "in a hurry" nage who may not turn all the way to protect you.
As to ikkyo, I pretty much agree with you but there's some folks that it just plain hurts with. It's the same problem as above in that the nice ikkyo turns into an arm bar or "I must pin you". Often found when someone's technique breaks down.