RUMFORD, Maine — The major story to come out of the final race of the 2012 U.S. Cross Country Championships was Torin Koos’s disqualification for obstruction of competition (which he plans to appeal). But in addition to the drama, an entire classic sprint day went on at Black Mountain. When the A-final field took the line Sunday afternoon, it was difficult to know what to expect. Koos seemed like the only safe bet to be...