I actually think Pac has an easier time with prime Whitaker than prime Mayweather. Pac is open to the right hand from the orthodox stance and Whitaker was a southpaw. Whitaker also didn't move as much as he tended to stand right in front of his opponents and slip shots. But Whitaker was a truly exceptional defensive fighter. He didn't need to move as much because he was still untouchable even when in close and out of position, never seen another fighter slip out of a corner then back up into the corner again and still slip every shot thrown at him. Pac with his speed and work rate will have his moments but Whitaker wins a comfortable decision.
Bad style match up for Pac. The May-Pac fight showed that prime for prime Pac probably just beats Floyd, but Whitaker was on another level to Mayweather.
I don't know how you came to that conclusion? Especially when considering PBF wasn't prime in that fight either.
Shot Pacquiao backed him to the ropes and gave Mayweather physical problems with 1 arm. Pacquiao ain't even vicious anymore.