Eugene, this doesn't sound good. I respect your experience, but personally I wouldn't want to put more strain on my ankle joint or force them to work harder. I like trail runners (I've been using Inov8s and NB MT100s) because they let my foot and ankle work naturally. As you say, the soles of boots are stiff, and when I step on a rock that I can't feel in boots, the whole thing tips off balance, tweaking my ankle. With trail runners I can both feel that rock and adjust, and twist my foot naturally to keep my balance. It is my personal belief that stiff-soled shoes are mostly to blame for rolled ankles while hiking.