What do you mean by "Parametric Infill Generator"? Are you thinking variable infill density within a layer (say 30% at the outer walls, but only 15% in the middle)? Or variable along the vertical axis of the part?
I would like to have the ability to insert variable infill densities in either the XY plane or vertically.
I was thinking more of modifying the pattern of the infill through noise generation like this in Zbrush: https://youtu.be/A7ter6hcTIA
Variable density through XYZ should be possible. MeshMixer does something similar with gradients.