Mosley was already an ATG before his win against Margarito and let's not get carried away here, Margarito is not in Mosley's class or Oscar's for that matter. He beat Cintron and yes he beat Cotto, how Cotto managed to lose that fight i still don't know because i don't think Margarito is in his class either.
I liken Margarito to the EPL, he was top of the championship league and gets promoted to the Premier League, he surprisngly wins his first match then kapow is brought back down to earth when he tackles the 'Arsenal' of Suger Shane Mosley.
As for Mosley one of my favourite fighters and people in boxing i would have loved to see him fight Tszyu back in 1999. He chose to chase Oscar and it was a smart move both financially and career wise.
He really needs Floyd now or Cotto again to cement his place in Boxings top 20 ATGs. He is 37 and probably has one or two big fights left in him but guys like Margarito are a punching bag for Sugar Shane. Floyd, Cotto or Williams could be a different story altogether.