As I understood the ruling, it was made with reference to his specific blades in particular. The ruling did not include all blades per se, but his specific blades. And the advantage that he gained was not so much in speed (as was noted above,) but that he required less energy to achieve the speed he did attain, and he had no lower leg muscle discomfort. As any runner knows, its not your bones that make you quit running, or that cramp up, or that seem to take a vacation every once in awhile no matter how hard you've trained, its your muscles and other soft tissues. He has no danger of sprains, ligament damage, etc.
I equate this with the fellow a few years ago who wanted to compete in the PGA tour but he had a muscle problem that prevented him from walking a full 18 holes. He wanted to use a cart, the PGA denied his request and he sued - and he eventually won. I don't know what ever became of the golfer. He really wasn't all that good. But the issue was one of fairness - everyone else had to be on their feet and walk over a 6 or 7 thousand foot course. He had a distinct advantage over all of his fellow competitors, as he just had to walk a few hundred. The PGA had it right, the courts screwed it up.
Let the sports agencies police their own turf. Keep the courts out of it.