Of course some figures need more polys.

If you only render young women with an average body-mass index, then yes, all you have to worry about is that the boobs won't look too blocky.

But if you also want to depict realistic looking males as well as bodytypes that deviate slightly from the strictly "average" then you'll need a "little" more than just the bare minimum of polygons.

I did a lot of experimenting in the past years because, yes, I wanted my figures to be as efficient and lo-poly as possible.

But for me the lowest threshold was 40.000 polys.

Anything below that will look decidedly "game figure" quality unless you use elaborate displacement maps.

(Which introduce a whole new set of problems)