I know the reason why Hingis lost early in slams this year....
Exactly the same thing happened to Andre Agassi in 1998. He started the year ranked 140 and returned to the top 15 by the end of 1998. He spent all of 1998 trying to climb the rankings and he consequently played each tournament like it was a grand slam, and played too many tournaments. He wore himself out and didn't peak for the slams, he lost early in all the slams in 1998 despite winning 6 tournaments. Then in 1999 he won the French Open, made the final of Wimbledon and won the US Open. He no longer concerned himself with winning every first tier tournament and he made sure he peaked for the slams.
This year Hingis didin't peak for the slams. She concerned herself with climbing the rankings and did a great job of that. However she played her best tennis too randomly and not in the slams. Next year she won't be chasing a top 10 ranking, cos she already will be in the top 10 and can therefore focus entirely on the slams. She can stay fresh close to the slams and she will make semis and finals in the slams and have a chance to win them. 2006 is the year she got her feet wet and probably reach top 6. 2007 will be her year to win slams.
Martina Hingis has won Roland Garros 2007!!!!!!!!!!