A lot of the fitting problems we experience come from a bad figure shape to begin with.
Different body types, different artistic styles, etc..
The human body is a strangely diverse bit of engineering. There's so much variability! It seems strange, I know, but after years of trying to figure out patterns of variation, using whatever scientific texts I could grab, I've come to one conclusion - Excepting within a broad scope of extremes with variations relative to physical necessity, there isn't any dependable "rule." (Human growth patterns, certain predictable measurement variability regarding fat deposits, typical limb length relative to major supporting structures, ethnic/racial bone structure and specific features, etc, being more predictable, but still a great deal of variety.)
I'm sure gazelles can tell each other apart. There may even be something the gazelles consider endomorphic, exomorphic, whatsomorphic... But, with humans, there doesn't seem to be a hard-and-fast rule. One picture of a herd of gazelles vs a "herd" of humans should tell the tale.
There is somewhat of an exception, though when it comes down to how "art" perceives human body types, specifically the "heroic" stature vs "realistic" stature. These can, though not always, have widely differing relative measurements, since one of them is an idealized, classical, figure and reality, by definition in our humble world, isn't "ideal." :)
Take the base V4 model, for instance. That woman doesn't exist. For one, she would have severe back troubles... I also have doubts concerning the health of her hip joints. Some of the musculature isn't "natural" relative to other bits of musculature. (She skipped arm day at the gym.. or the other way around.) Now, don't mistake that this is criticism of the model - It's an outstanding 3D model. BUT, if one tries to "fit" clothing made for a figure of this type to a "realistically" proportioned figure, one is going to encounter issues that are difficult for an entirely automated process to correct.
Human variability outside of certain specific features, like those often linked to race or known diseases/defects, is only as predictable as the physiological/physical necessities dictated by certain extremes. Even then, it's not so darn predictable...
ie: If cloth didn't stretch to accommodate a wide variety of measurements... we'd be severely unfashionable. :) In Poser, et al, getting good "fits" between items made for differing base body types will likely always require direct human intervention.