This is very hard to do from a practical standpoint unfortunately and not a big enough seller (when the status quo is almost no one offers any serious customization) to justify the amount of effort it would take.That's why there should be a adjustable option to tighten them or something to make them fit nicely. When it comes down to customization you need a lot of options to actually create a good decent un-generic characters.
Worse it can make it harder for casuals to use (which is the whole point) and while it'd be awesome to have a casual and a pro mode for a character builder, you'd be more likely to see that from a new game that's built around that idea rather than something that's a side feature.