Yes, Williams has size and high output....I question his durability though, and his aggressive style will get him TKO'd against Pacquiao....
No way he can take the shots Margo took. All he has to do is ask for a drug test though and no fight.
Pacquiao did not beat the Margarito that Williams fought. Williams beat a Margarito with loaded gloves. Pacquaio beat a plaster free Margarito and still sustained a great deal of damage. Margarito landed regularly on Pacquio. He landed triple jabs, hooks, uppercuts. Paul Williams is a faster, taller, longer, and much more mobile version of Margarito who I think would TKO Pacquaio.
I think in terms of reach/height for an opponent, Margarito was the limit for Pacman. PW is a HW in a 154 lb body. It would be comical watching Pacman trying to land on PW's chin, he would literally have to be punching upwards at a steep angle. That alone will greatly diminish Pacman's power. Just too much of a difference in height/reach for Pacman to overcome IMO.