I think the problem only occurs when he is running to retrieve a high bouncing ball, especially to his backhand. He sends it back with less pace or accuracy, setting it up in his opponents hittingzone. He seems to handle kick serves to his backhand ok, especially because he is ready for these and has less ground to cover to get to these.
It is hard to flatten out a high bouncing ball hit at you with a lot of power, so those less powerful players may have been the ones he "chopped up".
However, Agassi also hits a heavy ball...he was able to handle Agassi I believe only through the strength of his serve during the quarterfinals. Serving at only 30% isn't going to help you win very many matches. Even though he was able to break Moya's serve, he wasn't able to hold his own, something he does so well usually by getting cheap points off the first serve. His first serve was lost somewhere in the wilderness during that final.