walking pac down would negate his reach and play right into pacs hands. I don't even know how this version of Floyd is going to attempt to attack pac. if he takes the first 3/4 rounds to figure him out he might get hurt or be down 3/4 rounds which would hurt his chances of implementing any game plan they drew up
I think he might walk him down later in the fight. hes done this with all the other south paws he has faced. Yes Manny is better but I get the feeling he will start to counter him, Manny will slow down, become more stationary and less active with his hands and then Floyd will work the body and start backing him up
Early in the fight, Mayweather will not walk to Pacquiao. By round 8 or 9 he will walk to Pacquiao in stretches (he always mixes between walking to and out of range later in fights).
Floyd will fight at distance, but I also think he will rough up Pacquiao. He will either be too far for Pacquiao to hit or to close for Pacquiao to get anything on his punches.