I think most of Broner's success is just that this is an exceptionally weak era after an exceptionally good one. Litzau, Cabellero, and limited Ponce are just not very good fighters (though Ponce has one GREAT attribute: his punch). Juanma Lopez, Amir Khan, and Linares are the perfect examples of the modern "prospect" - they can lose to ordinary fighters on any given night. Broner is a good fighter so he looks golden, but I don't see enough fluidity in his game at this point to be effective against the extremely dynamic versions of atg fighters like Shane Mosley or, let's say, Duran at 135. I feel like Broner is just big fish in a very small pond right now - all these up and comers have egregious flaws to their games (to be fair, he doesn't have glaring flaws except actually letting his hands go early, something Floyd did well at 130). Russell is about the only young prospect that I think would do well in the time when Chavez and Whitaker where on the way out and oscar, shane, and those guys were coming up. I just think it's a much more limited and flawed talent pool now, much inferior to the prime time of Barrera, Morales, Marquez, Kevin Kelley, Hamed, at the low weight classses etc.
Shane had a decent jab at 135, particularly to the body... I've said this before but outside of Roberto Duran (and even he would have trouble), there's not a fighter in the history of boxing who would beat Shane Mosley at 135. He was simply incredible, physically too much for pretty much anyone, EVER.