Originally Posted by tudwell
I don't know about that. He's got Djokovic to challenge him at the Australian, Nadal who he would never beat at the French (and if he did, Federer and Djokovic are still above him), and he'd most likely not be able to luck out and play a headcase like Goran in a Wimbledon final. It's likely he wouldn't win the career slam and possible he wouldn't win a single slam off hard court (although it's also possible he would). His success at the U.S. Open would probably increase, though. No one's been dominant there since Federer's begun to decline, so Agassi wouldn't run into a Sampras-caliber player time and time again like he did in his real career.
You can point to similar reasons why Agassi shouldn't have won Wimbledon and the French Open when he did win them. However, he did win them.