On topic:
How would you play as a "normal joe" in a video game where you jump impossible heights and pull bullets out with the power of your pecks? You can't. It's called "willing suspension of disbelief", and it's a lot harder to believe that Fat Joe can run for hours on end with heavy weaponry, jump around like Mario, and dodge bullets for days on end than, say, some guy who looks like he hasn't missed a six hour workout a day in his life. Chances are, these kinds of people are the same ones that look pretty good, what with their uber-pecks and perfectly chiseled faces. Or, in the case of girls because that's the only thing that these threads ever focus on, massive mammaries, tight buttocks, and a six pack that will always be shown.
Also, humans like to look at pretty people. Do you people believe that pretty people can't be well characterized?
It is a shame when a girl walks on screen whose personality can be summed up with the word "*****". But that's bad writing, not bad character design. I don't hear anyone complaining about Morrigan, but take a look at her picture on the internet. Or the girl from Mirror's Edge, but again, take a look at her picture.
My point is that I don't want to play as ugly people. I got enough ugly for myself. Decency and some realism in breast size would be nice, but many Escapists seem to think that any character that looks halfway attractive is automatically bad.