The fact that Coin beat Ivanovic shows the problem at the top of the women's game... there's just no real quality at the moment, as Ivanovic isn't playing like a number 1 (or even 2 or 3 based on the whole season, winning just 2 titles), but is there by default.

Coin wasn't exactly looking like a special player, and her record this year, which is pretty average is probably a better assessment of where's she at in terms of ability

Ivanovic - won just 2 titles this year, and since Roland Garrs has really struggled
Jankovic - chokes in every major final, and although she's a great defender, can't really attack that well (and she's too whiny for me to like her)
Kuznetzova - good player, but she isn't a world number 1 as she seems to have some inexplicable losses, but given her draw, could well make the final and take the number 1 spot
Williams Sisters - don't play enough tournaments, and if either got to number 1 with their schedule, it would be embarassing for the WTA
Sharapova - gone backwards in the last year and has lost her serve and forehand, showing her to the be a huge 1 trick-pony
Dementieva - not a number 1, but seems to be the only one who is improving her game at the moment, with the serve an awful lot better - will win a Slam in the next 2 years

The WTA just needs someone to show themselves to be a force at the top of the game, as otherwise it's going through a period of mediocraty (yeah, it's exciting, as everyone can beat everyone, but doesn't help the tour)

I bet Henin is kicking herself at retiring, as she'd probably still be number 1 now, even if she only had some average results