I think sex appeal has its place in games (Though it is overdone). I mean, its fantasy, I have no problem with a game having a ton of sexy ladies, and equal number of guys as well. In a game thats stylistic and made to be a fun time and a less realistic or gritty atmosphere, then fine. Just keep it out of, say, Call of Duty. Keep it in over the top action games or whatever.
I think girls are more prone to look at a hot guy and think "Oh, hes nice", while a guy is more apt to not be capable of getting over, "OMG Boobies". And a game designer is likely to gravitate towards the obsessive market...look at MMOs. Likely explains why the guys in games are just about always solid, good looking guys, and girls have usually become parody's of beauty, taken to an extreme caricature
(And yes, I am going to be Heterocentric in this post. Because I don't have all night, and would like to write a post, not a book)
Personally, i think it's getting stupid, and would like a lot of designers to learn that big breasts does not automatically equal sexy. Soul Calibur is a good example here. Personally, I think Ivy and Taki, though I like at least Ivy to no end, are the least attractive girls in the game. Seung Mina is likely my favorite...then again I mainly play her, so bias there...however, next on the list is quite possibly Talim, held back only because she looks a bit too young, but is easily the least well endowed of them all. In DOA, Lei Feng probally takes the gold, but Kasumi would if she was better proportioned...and I mainly play Kasumi, so im biased to like her more! Other sexy girls on almost everybody's list is Alyx Vance, a very realistic looking girl, obviously athletic and correctly proportioned. I say she blows, say, Bloodrayne, out of the water. no double Ds needed.
If game designers want to make sexy female characters, fine, the guy in me can dig it, but take a hint from how you usually make sexy guys. Take normal female body you see all around you, add tone, curves, some striking cosmetic features that may require a little bit of creativity on your part in understanding of the psychology of attraction, show just enough skin to say, "Alluring and tempting" and not, "Whoreish", and then and only then, maybe add a cup size. You will have the demographic of guys old enough for jobs drooling, and only mildly dissapoint the junior high crowd. And, you will have a standard of beauty that a girl might be able to shoot for and actually become more attractive and healthy, instead of destroying themselves, likely winning a lot of respect from girl gamers
And if that sounded sexist, I will freely admit that i would not mind looking more like any number of guy characters, because sometimes standards of beauty actually ARE good things to shoot for because it is healthier as well as more aestetically pleasing, and can be obtained by normal human beings willing to put forth a less then obsessive amount of effort.