I agree to some extent. Pacquiao should've pushed a bit harder, especially in the last few rounds (I was rather surprised that the pace didn't jump up at the end), but a lot of those things are of course much easier said than done. Mayweather has great footwork, so getting around on his outside and trapping him in corners is naturally going to be very difficult as a result (for instance the absolute basics against a southpaw is to rotate clockwise to match them and make sure you're on the outside instead of them), and I felt he was doing a really, really good job at slowing the pace of the fight down.
While it's been a few hours so it's no longer 100% clear in my mind, I do think Pacquiao's approach to the fight was pretty good (I thought it was basically even in actual terms at the end). Just trying to hammer a really good counter-puncher is something (imo) that will get you heavily punished unless you pick the timing of when to do it right (which Manny did), I just think he really needed to up the pace and pressure in the last few rounds, and the couple of moments where he had a big advantage. I think he let Mayweather off a bit too quickly whenever he actually hurt him, as he'd hammer him for a bit while Mayweather bunkered up and then went back immediately to regular pace, instead of upping the pressure and not giving him as easy a time to recover.
I'd probably have to watch it again to really give a good opinion on it though.