Comment by mcdeltat

> mapping of specific nerves to intensity of feeling on the CNS would imply complex hardcoding of something which is much easier to solve with "this place important, have more nerves"

Not saying your answer is right or wrong, but I don't think this is a sufficient explanation. If the body can differentiate areas enough to produce more nerves in one area, then it could plausibly instead produce fewer nerves which inherently produce a stronger signal - just as we have nerves which respond differently to different stimuli (e.g. heat, light, etc). Also it could be neither and we kinda randomly ended up with what we have because no option was strongly disadvantageous at the time.