Mosley is the worst matchup out there for Pacquiao, 147 and under. He's considered past his best, but he's still blindingly fast and hits very hard. And with a chin like Mosley's, Pacquiao aint knocking him out. Tough, tough fight.
I don't think any legit big welter is a good fight for Pacquaio. The guy's current physical shape is an average LWW's at most, even Roach admitted they reached PacMan's physical limits. Calderon might beat JuanMa with awesome speed, counterpunching, defense and natural gifts (honestly, I doubt), but he'd still have to fight a guy WAAAAAAAY bigger and stronger than him. PacMan is blinding fast, very powerful with excellent stamina and movement, but he just deserves better than fighting guys who weight 160 pounds or more fight night. PacMan blew out Hatton, yes, but don't forget he still got caught by a few clean blows, watch the 2nd round again, a punch-drunk Hatton managed to land some. Well, it's a fight and that happens, but imagine PacMan taking or even partially taking shots that KOd MW sized Margarito or that dropped Quinatana (vs. Cotto and Williams). Mob Arum is seriously the most pathetic f*cker out there if he's ready to let his two cash cows fight each other and keep all the promotional money for himself. Cotto, Mosley, Williams are too big for Pacquiao, the only welter who fights in his weight range is Mayweather.
Shane is TOO BIG / TOO STRONG/ GOOD CHIN / GREAT SKILLS Hatton may have had a chance with pac if he had any defence