The only way this match "saves" the sport is if Pacpaca loses in a squeaker by decision. Then the rematch comes into play.
I'm not so sure. Mayweather is very, very careful about his career and legacy. Sure, he loves money, but he's got a ton of that. If he barely won, he's still go on boasting how he won and is the greatest ever, and wouldn't dare risk a rematch to someone at this point he barely beat. He's not the kind of fighter out to prove anything that he doesn't think his [imo constructed] record doesn't prove.
I think the only way a rematch would happen is if Pacquiao barely won. Then, Mayweather would try to avenge the loss from a record standpoint against an opponent he knew wasn't that much better than him.
Of course, Mayweather is great at fighting people who won't really challenge him. In part, because he is great. But also because he designs it that way. He knows if he can retire at 50-0 it will mean something. Retiring with 60+ wins and 3-7 losses like a lot of great Hall of Fame fighters? Nah, that's just poor scheduling and bad management.
I don't think there was any real chance of Pacquiao winning, and neither did Mayweather, which is why we got this fight at all now, and didn't at any time in the past.
In short, great boxer, woman-beating piece of shit who ducks fights and is more concerned with money and the talking points of his legacy statistically than being respected as a gritty, ballsy fighter. It's not a right or wrong approach, just... different?