So I had an idea for corruption/pure difference that I think are already present in some form in some scenes; have corruption level change how loving or brutal you are in sex scenes to some degree. If your corruption is low and you sex someone in a random encounter you carefully tease their openings, fingering them, getting them into it, before carefully inserting, and gently and lovingly petting and kissing them and striving to make them feel good, even if it's someone like the Painted Demon or similar corrupted being (which might leave them very confused and vulnerable at the end), versus high corruption the lines where you'd carefully arouse them has you slapping their ass, bending them over and just thrusting in hard with no consideration for anything but your own pleasure, with them letting out a pained moan that slowly change into moans of pleasure. Kissing/petting scenes change to spitting, slapping and other derogatory actions, and at the end demon types seem like they got exactly what they wanted, but less corrupt ones like Byvernia or Gytha seem resentful and ashamed.
Basically rather than complete rewrites of the existing scenes, I'm talking basically a sentence or two inserted early on and at the end, and then some minor extra parts for the petting/slapping stuff during the scene. This wouldn't also be something for all scenes, just a select amount, and some characters like Romanced Kas, high confidence Ryn etc would be just completely exempt, if you bothered taking the time to raise Ryn's confidence then even your demonic-looking dark knight is probably into maintaining that (EDIT: Though I just realized a good example of where this mechanic is already present is Ryn's sleep scenes actually, which have these types of differences depending on your corruption), but someone like Elthara on the other hand might be a viable target for loving and tormenting alike, and in her case would probably get off on both.