How much did Pacquiao really improve between Morales I and II?

A lot of people talk about how much Pacquiao improved between the first and second Morales fights, but if you think about it, it couldn't have been THAT much. For one Barerra was able to give him trouble in their rematch, something he failed to do back when they fought at 126. Marquez was also able to give Pacquiao as much trouble as he did in the first fight (although to be fair, his shots didn't have as much of an effect, but that could have also been Marquez's age kicking in). A lot of people say he won both of those fights. I'm not trying to knock Pacquiao or anything, because after Marquez II he became a completely different fighter. That's just a question that's been on my mind for quite some time.