Nadal would run down balls that Agassi never could vs Sampras. So Nadal would be beating Sampras regularly in the 90s. Hewitt gave Sampras fits, and he's a very light/untalented version of Nadal. And Nadal would be out-maneuvering Agassi and beating him too. And Nadal would still be beating Federer in the 90s, on clay more than ever, because that was far slower clay than the clay they have today. On hardcourts, yeah Nadal would love the bouncy rebound ace of Australia, and would beat Federer there everytime. US Open, it would be a toss-up. Nadal, as he's said before, can use his big serve when required, so he would on the ultra-fast US Open 90s court.
Of the 46 total titles that Nadal have won, could you list me the titles that Nadal won on fast surfaces with low bounce? Off the top of my head, he has only 1 indoor which was in 2005 Madrid when he was 2 sets down to Lubicic. Won Dubai in 2006. He never won fast Cinci., never won the Master Cup(now is call WTF).