Who has the better win over Hatton?

I think you make a good point except you overlook the way a fighter trains. When Hatton was training for Pacquiao, he was doing everything he ever did. He knew exactly when he should be at 150lbs, when he should be at 145lbs, how he should cut to 140lbs and effectively bulk up for the fight. This is the issue that guys have when they first move up in weight. It's not simply an issue with putting the weight on, it's how they manage that weight. When Hatton fought Mayweather, his training was completely different to how it had been before apart from the Collazo fight, when he also looked sluggish.

On paper, Mayweather wasn't much, if any, bigger than Hatton. Though because of the training he went through, the emphasis on additional size and strength and things like that, Hatton wasn't as effective at 147 as he was at 140. Had Hatton trained for Mayweather like it was a 140lb fight, he'd have been in better condition.

Mayweather's win over him was good but Pacquiao beat a better version. Hatton simply didn't suit 147lbs because he lacked natural strength and tried to add it instead. It just didn't work.