It's already normal for women to sexualize men the same way. Heck, I was surprised when I found out Ayn Rand got downright ridiculous about it (I expected it for romance novels and the like, but not from her in that one fiction book of hers I tried to get through).
The problem, at least from my perspective, is that women tend to be relegated to eye candy and such as their primary aspect, whereas men can be sexy AND so much more at the same time, and having so much else to develop then men can get away with not being particularly hot looking or sexy in some other way (that said, I can't ever see a ship like Clem + Buffy taking off like Spuffy or Bangel, especially not among the female demographic). And a man can save other men, but a woman is (at least in stories, which often filter into social expectations) thought to "owe" a guy for doing the same...even worse, a guy saved by a woman is generally played for laughs or awkward (though I think male writers are more likely to take it seriously than female authors), and like the trope of conflating women with children (all to be saved by the menfolk), it implies women are less capable than men and thus less deserving of equality. It also teaches women that her power is in men rather than herself.
And another problem is the "evil is sexy" (seems guys like badness, too, though that villainous females tend to be seductive, show more skin, and as a rule are portrayed as having bigger breasts than good girls only increases that trend). When I was a small child, it got problematic a couple of times because when we children were reenacting some movie, the boys wanted to divide into "good and bad guys" while many girls wanted to be the prettiest character (as in who the boys thought was prettiest) without regards to whether she was a heroine or villain. This isn't as shallow as it may seem (no more than dividing teams into white and black hats anyway), it's just girls generally learn to prioritize differently based on the media and even the real life examples around her. And while sexy is a bonus for a man (though bordering near crucial when seen through the female gaze), it's crucial for a woman (at least that's the message). Men are ultimately measured by what they can accomplish while women are measured by how appealing they are to men...because gods forbid they have to do things for themselves.
I'm independent, and my own mother sees that as impressive as the blind person who has other senses sharpened to an incredibly degree...that is she can grudgingly admire it, but she's more inclined to pity than envy me, as it was her lesson to me (though not explicitly stated) that men's power is in the world, while a woman's power is in men (though she's not submissive, but she is--or at least once was--seductive).
It's funny...when I was 10, I was assigned to rewrite a faerie tale from some other perspective than the heroine's. I chose
Vasilisa the Beautiful in which I portrayed Vasilisa as a conniving sorceress while Baba Yaga was a kindly crone she learned from. And then Vasilisa enchanted the tsar (rather than him falling in love with her beauty as stated in the tale) and then portrayed Baba Yaga as a demon as BY was the only one who could stop Vasilisa now, and thus turned BY into an enemy of the state so that the crone had to flee into the wilderness where she was a magical rebel hero defending the oppressed while evading the law (and helping others do so). Two teachers and another adult raved on how original it was (and there were many positive comments by the teacher grading left on it as well) and for once I got high praise in school. The point being that having the heroine be ugly but someone to root for while the wicked witch was beautiful was downright mind blowing to them as that's not how it's done, and they were amazed I even thought of it, especially at the age of 10. (In retrospect I realize that such occurred to me because of my mother being a former model who bragged of evil things she did and how easily she could wrap men around her finger while demonizing my grandmother, and that just got transferred to my rewrite of the faerie tale--though reading material as
The Witch Next Door also helped to inspire me.)
See also
beauty equals goodness
One problem is trying to avoid this is going the opposite way to remove anything that is sexy about her (for example, automatically dismissing Lara Croft simply because she has big boobs as if that negates all else about the character) while men are still allowed to be sexy and everything else. If a woman being sexy and attractive is made into some sin then even many women aren't going to like her or want to be her then, and it ends up stigmatizing and limiting women in a different way. From my POV, it's not that sexiness is bad, but that it's required for women, and women find it much harder to break out of that limitation. Women should be as free as men to be sexy and/or anything else, and the definition of sexy shouldn't be so limited.