Pacquiao is a fighter steep in decline. He ain't doing better against a master like Floyd in a rematch - he will do worse. Bank on it. Floyd is brilliant at making adjustments in rematches. Pacquiao is awful at it. :smoke
Basically. No other opponent stands a chance. No one. Not Garcia (vomit-inducing). Not Thurman (100% no). Not Canelo (laughable). Not Cotto (Another UD). Not even Pacquiao himself, but at least I'll be able to see them together one more time. Plus, the promotion would be hella fun.
I'm trying to imagine an actual healthy pacquiao doing worse. even if he doesn't do better, he won't do worse. he was rock bottom. he can't do worse other than being knocked out, and with that, at least the fight will be interesting.
Mayweather had a torn cuff against Castillo the first time, so no. Mayweather beat Castillo cleanly in the rematch and would have in the first if he was healthy.
You're underestimating Floyd, and grossly overestimating Pacquiao. Pac's feet are gone. He's no longer a special fighter. Compared to what he was, he's a has-been, and he's exhibited steady decline since around the time of the Mosley fight. Floyd always does better in rematches. He tamed Pacquiao with relative ease because he had vastly superior footwork. Pac's trumped up shoulder injury ain't going to change anything if he's "healthy". He doesn't have the feet to compete with Floyd, bottom line.
So, you're basically saying that Floyd beat a shot Pacquiao? That's not giving Floyd any credit. :nono