Yes, beauty standards change over time, but recent studies have shown the fit woman ideal is always there.
But I have to agree with some of the guys over here, people (both men and women) prefer looking at nice looking people, let's be honest. And in fantasy settings there are more male stereotypes around that can be ugly and still work as a miniature.
And more importantly: for a female miniature to look like a woman, certain aspects have to be exaggerated a bit, such as the female bits and the body shape. A miniature of an average woman with small breasts in practical clothing would pretty much look like guy. You can't sculpt all the subtle differences between man and woman on a small scale like the minis we like.