While a lot of people have pointed out that it *does* go both ways, I think the OP is right in that, really, there's a higher instance of "dollitude" going into the art.
There are, for example, few scarred women. If you look at most D&D art, there *is* a lot of midriff, and it seems women adventurers spend a lot of time focusing on their hair. And, there's also a huge number of women in the books entirely - I'd definately say more than half. You can tell the books are aimed at male gamers.
As an example of this, look at the "class acts" in the last issue of DRAGON.
The "adventurer" class act has a woman rogue wearing basically a bikini top, and really tight pants that she has (literally) half pulled down, showing a piece of thong underwear.
The "arcane" class act shows Mialee, reading a book. Now, while this picture isn't all that "sexy", that's just because of her pose. Remember what Mialee looks like in general - flowing hair, and definate cleavage.
Then we have the "Divine" picture. I actually like this one -a woman in armour, definately hurt, witih an arrow in her leg and holding up her mace defiantly. About the only complaint I'd have is the, um, rather large "boobplates" she seems to have in her armour. But, whatever.
When we have the "Warrior" CA. This girl actually does look like a warrior, except for the fact that her shirt is very silky, and, well, "clings". But, I'm cool with it.
Then, we have "Finale". Here's an orc. Less detail on his face, more on his armour, which is, by the way, a lot bulkier. There's no hesitation in making him "ugly".
Out of five pictures, only one is of a male.
And look at some of the other art, in the same magazine! on page 108, we have a woman in a "one-piece" suit of armour, where the leg protection amounts to a miniskirt, and the armour itself shows a hint of cleavage.
Compare the elven women on page 103 with the elven men in the same picture. Guess who shows more skin? In fact, all three of the men are very covered up, while the women are not.
Eli Tomorast, on page 56, is a male showing off some skin; in that same article, Eclavdra (pg 60) is a female with huge "boob armour", Iggwilv dresses slightly scandalously, and Lloth is wearing a bikini. In that article, 100% of the women are skimpy in one way or another, while only one picture out of, what, 6? of the men even show a small amount of bare skin!
Even the Marilith, on page 50, has cleavage. And that beautiful picture on page 42 shows the contrast between man and woman perfectly - compare how the woman looks (her armour has been split, and stiched, to show cleavage; her hair is flowing in the wind; and much of her armour has been cut away, to show perfect skin) with how the male looks (bulky, bulky armour that, while not very realistic, seems like it'd offer a bit more protection; much less emphasis on the face).
By the way, I don't mean to pick on Paizo. I love their stuff, and I prefer their art over the PHB. And it's a wider trend - women tend to be more sexualized in art than men. Hell, I have a bunch of Reaper Minis in front of me - and the males are all wearing pratical armour, while two of the three women minis in front of me are wearing bikini pieces or "cleavage armour".
(I also have a man in a conan-look, basically naked; and a very cool-looking woman in leather armour that isn't implicitly sexual, so there is at least a little bit to say for Reaper, right there).
So, yeah, I'm going to have to go with the OP. There *is* a sexualization of women in the art of D&D that is not present in the same degree as men, if not in the actual rules/content of the game itself. And, yeah, I'd like to see some dwarven women in the art. And a few scarred lady fighters (and not "sexy scars", either!). And I'd rather have women be found in about 50% of the pictures, not the 60-70% I'd think there is now.