Re: How Long Until The Next GREAT Player?
Slams on their own are not what make players great, it's their whole careers that do. I agree with the OP that there aren't any outstanding young players, but whether or not they have reached a slam SF doesn't mean they aren't great. If a player were to go on a tear and win a number of big titles in a row, they would also look like a potential "great".
Venus is of course a great player. As are Henin, Davenport, Hingis, ASV etc. (and likely Sharapova in a few more years). Players that got to the top and remained there, dominated and made their mark on a certain era. There are different levels, but to say any of these players are not greats is wrong. Navratilova, Graf and Evert are in a league of their own, Seles and Serena do not belong there.
Getting round to the question, well we had Henin on a roll for 2 years and who knows where she could have placed herself had she kept on for another few years. The top of the game is struggling right now, but of all the players in the elite I think Ivanovic and Sharapova will be the ones to become greats.