Okay, and he MAY beat them. Until then he is 25 and has never fought above C level opposition. I'd save the hype for at least the first fight where he is not a massive favorite.
Unless you consider Shawn Porter a great fighter, I'm not sure what Kell Brook has done to prove his greatness either. Squeaking out a decision over Porter and he's fought two bums since then. And where the hell is Marcos Maidana? Did he go into hiding after the second Mayweather fight?
Actually Mayweather SHOULD fight Brook in London and make it a nice change from the usual pattern. But he won't. He'll fight another fight at MGM on September 12, same old shit, Justin Bieber and all.