Jon, as you probably know, the anchor points that Rick Welch suggests, which are the tip of the nose and the lobe of the ear, are both soft points. In fact, in my first lesson with him, when he noticed that the bow string was skimming my cheek and making a red mark, he suggested that I hold it further away from my face to avoid that.
I still use those two points, and have added a third, which is the bowstring pressing against my eyebrow. Plus, as Scott mentioned, I try to be aware of my back tension and alignment as my primary anchors.
I don't see any particular problem with the soft points, since if anything, they seem to be a little more precise than a hard point since they are sensitive to the touch and I can tell if I am a little off one way or the other. And, as has been mentioned, head movement and changes in body alignment can cause much greater errors than changes in anchor point on the face anyway.