When he founded Nike in 1972, CEO Phil Knight contended that if "five cool guys"--the best and most popular athletes--wore his shoes, other people would want to as well. The strategy worked wonderfully, of course, and now Nike controls an astounding 47% of the U.S. athletic-shoe market. But the brand has become too common to be cool. "I call it the Izod syndrome," says John Horan, publisher of Sporting Goods Intelligence, referring to the once-hip golf shirt. "Nike is everywhere." Brand expert Watts Wacker, chairman of the consulting firm FirstMatter, believes that the ubiquity of the Nike logo--the over-Swooshing of America--turns off important core consumers, the 12- to 24-year-olds. "When I was growing up, we used to say that rooting for the Yankees is like rooting for U.S. Steel," Wacker says. "Today, rooting for Nike is like rooting for…