Nike (NKE -1.15%) is the largest athletic apparel company in the world, by far. But it's been experiencing severe setbacks over the past few years, and its stock price reflects that. It's down 23% this year alone, and down 67% from its all-time highs.Is this an exciting opportunity to buy on the dip, or a struggling company to avoid?Why can't Nike "just do it"?Nike has a compelling branding position as the leader in its industry. It's a premium label that appeals to a mass audience. In general, that means i ...