the only thing i can imagine that is of any functional significance is the weight of the blade and scales. i believe the desired location for the center of mass when the razor is open (180 degrees, or pi), is at the pivot pin.
in my mind lighter scales are less of a problem than heavy ones as the heavy ones will tend to twist the blade as you shave, so you have to put more effort with your fingers to hold it at the correct angle.

Edit: looks like Alex types faster than me ... and I was thinking in the right direction.