Pacquio is not in his prime. Personally speaking, this fight should have happened in 2009/10. Additionally, respect to mayweather for what he has done, but Pacquio was injured and not the Pacquio of old, and i think for an attacker like Pac-man you need to be younger and more in your prime.
Not to take anything away from mayweather who would have made it harder for him even if he was in his prime by evading and running away with his great defense, but this fight should have happened when paquio was in his prime.