I just think that if you're going to include a slider for something, it should have a significant difference from one side of the slider to the other.
If the resources required to support a variety of body types is too high, I understand that. But then don't put in a slider to adjust body type, and there will be less of an expectation that you should be able to make a character that you can't. When the slider does so very little, all it serves to do is draw attention to the limitations of the character customization, rather than enhance it.
For me, I like the idea of having the option for making beefier female characters, even though I know that I personally would rarely (if ever) use it. I have a thing for slim, elegant, characters that are fast rather than strong, so rippling biceps aren't really my thing. But not every possible character has to be one that I personally like, y'know? And, in fact, if every possible character WAS the type that I like most, games would be the worse for it.