No, I think you're overanalyzing. Sherman isn't a narcissist (well, anymore than most pro athletes are).
To be honest, I think his whole persona is a veneer that exists to get people to have exactly this conversation. Sherman's trending on Twitter, Facebook, Google... Sherman's everywhere today. I think the reaction to his interview is hilarious, because everyone's falling for his 'WWF heel' persona. He switches between that and his 'Stanford-educated intellectual' persona at will. If anything, people should just be rolling their eyes at him. He wants to look like Kevin Garnett... but unlike Garnett he's not a legitimately bat**** insane mound of anger and hate.
Instead, he's an excellent cornerback who's better known than other excellent cornerbacks (Revis, Haden, Peterson, Talib, Tillman, Verner, Grimes) by the general public because of his heel persona. Revis, for example, remains a better player, but Sherman gets more props because of his media presence.
He's the player equivalent of Skip Bayless. He's trolling, and a bunch of people in this thread fell for it.