His only advantage is skill-wise, and that's a very slim margin overall, but defensively it's a wide margin. Pacquiao is a much better offensive fighter, there is no disputing it. His aim is to attack, and he does it well. Wondering where you got the physical and mental advantage from. It can't be hand speed because we know who wins that, it can't be physical size because De La Hoya, Cotto, Margarito, Algieri, etc. were all bigger than Pacquiao and got obliterated. Maybe you dumped elusiveness and defense into both the physical and boxing skill brackets?
Manny hasn't lost a fight in forever, last real losses were back vs. Morales. He didn't lose against Bradley, and he got caught vs. Marquez in a fight he was winning easily, but Pacquiao has never looked bad or gotten dominated, made to look bad, etc. in a very long time. He's pretty much always looked like the better fighter in every fight as far back as most people can remember. If Floyd does fight that way, Pacquiao will win an even easier decision than I predict. He better come to fight because Pacquiao is relentless and will take round after round unless Floyd participates.
Anyone who says that has it backwards, I think the Manny of 5 years ago loses to the Floyd of 5 years ago, but today's Manny beats today's Floyd. If Floyd manages to pull it off, I don't see any possible excuses, but I don't see it happening. Floyd isn't as active as he used to be, his footwork has really fallen off and he's mostly flat-footed nowadays.