Re: How Long Until The Next GREAT Player?
As someone said, I think Serena is the only one even close to be considered a truly distinguished "great" player. She has won all four majors at least once, has won everything in doubles, etc. etc. She is clearly the best person of this generation, and likely will be after they all retire. Although Seles and Serena aren't Evert-Navratilova-Graf level, they're realistically as close as we're going to get and they still separate themselves comfortably from their contemporaries.
So while Sharapova is clearly the best of her generation, it remains to be seen whether she could be the next great. If you compare her to Evert-Navratilova-Graf-Seles-Serena, she doesn't fit the pattern of raising the game to a new level. All of those players did. Sharapova is just a Seles clone, basically. A very good one at that, but she hasn't added anything new. Steffi Graf said Serena would be the best player of all time back in 1999 before she even won a slam, no one is saying that about Sharapova. Its not a knock on her, but she doesn't really do anything that others haven't before her.
Can she win 6+ slams and win the French Open? Its certainly possible. She hasn't shown the ability to be healthy for long stretches of time, which is worrisome. Also, her best tennis seems to come in spurts rather than in long periods (derailed by injuries, however). If Venus and Justine with their better talent couldn't do it though, I doubt she will.