Gianna Michaels would appear to score high in all the criteria. I've seen her gagged out horrifically on a number of occasions. Yet for all her feminine curvatures there is something unnervingly masculine about her. Masculine and untouchable. It appears to be nearly impossible to humiliate and degrade her properly. And I imagine her familial relationships aren't effected at all by her pornography. They probably just roll their eyes at her over it, like if she'd just gone base jumping or something. So obviously she does not make the cut.

Great porn insight here Windsock.
I have to agree that Annette and Bobbi never seemed humiliated by their degradation but turned on or a reasonable facsimile of it.
I think I'd have to reach back to something like the girl with Jamie Gillis in Winter Heat who he forces to deep throat him after slapping her around and tying his belt around her throat. Her whimpers and crying seem disturbingly real.
Or the infamous scene with Harry Reems playing a psychotic Vietnam Vet in Forced Entry where he forces a woman at gunpoint to sloppily blow him and ends the scene by cutting her throat.