To give you perspective, I am a woman, and I enjoy playing World of Warcraft. I've noticed this trend too.
Take for example Alexstrasza, who's model was introduced last expansion, and lore hounds were excited about, because she is the Dragon Queen, and arguably one of the most, if not the most powerful being in the game. Aaaaand she looks like this.
Then in Cataclysm they recycled her model for her sister, Ysera's new model. (Also a powerful dragon)
And Sylvanas, an extremely strong female character, not to mention the leader of the Forsaken, also uses the same model.
She's a very "love her or hate her" character, being that she's vindictive, manipulative, and two-faced, but it annoys me when someone like my friend claims that they love her "because boobs." Of course that may just be my stupid friend.
This is kind of one-sided, because the majority of the male races look like they're on steroids. Personally, I don't go for this, but YMMV.
Granted, a lot of people wouldn't go for some of the female races, considering some of them are gnomes, dwarves, goblins, cows, wolves, orcs, etc etc. But interestingly enough, the females of the "alien squid goat" races are considered to be one of the sexier races.
And then there's this.
I can't fault Blizzard for that one though. It was used in a hologram to distract men so that you could get to the quest objective.