It's true, Pacquiao does not need Mayweather. We all want to see it happen of course and it should when Mayweather beats Mosley. I don't think it will bother Pacman if it doesn't happen as his legacy is well assured.
Pacquiao has fought the best out there in recent years, from a rematch with Marquez (his toughest foe?) to De La Hoya, Hatton and Cotto stopping all three of the latter. Now tell me honestly, if anyone here thought 3 years ago that Pacquiao would KO all 3 of those guys then we would have had you certified. Pac will fight the winner of Mayweather V Mosley, it's the only fight left for him.