I mean, yeah that definitely works, but that's going to require someone to program that in separately and there to be enough support for it in the first place. SoAndSo already has something really interesting here and it can be patched way faster than entirely new content can be added. Also, there's not really any balance to that perk. The Painslut perk makes you incredibly vulnerable to lust damage even in its current state, which helps to balance the boost to damage resistance and creates a lot of interesting planning before entering an area like Myrellion or Zheng Shi that is swarming with enemies that deal hefty lust damage that I never engaged in when I just brute forced my way through every enemy without really thinking about what their attacks did. If the damage resistance was just made less ridiculously overpowered so it didn't actually make standard combat completely meaningless and the lust mechanic was straightened out a bit, it would be a far more nuanced mechanic than a simple subdermal armor layer. Even if you took the next logical step and said that theoretical armor gene mod reduced your agility or something to balance it out, simple number changes like that really just can't compare to something as interesting as exchanging weakness to one entire combat mechanic for another. Like I said, it's up to the creator of the perk to decide what to do with their own creation, but I feel like it could be so much more than it was intended to be and wanted them to hear that before thinking this was just a coding error that needs to be fixed simply because it didn't work as intended.
Let me just say that I mostly just repeatedly clicked attack until I inevitably won for most enemies in the game and only really read their defeat scenes until I got the Painslut perk, but after that I've been paying way more attention to the types of attacks enemies do and how to watch out for them because I know one or two well placed lust attacks can take me out in an instant. It adds tension where there previously was none, draws your attention to enemies that otherwise might have gone unnoticed, makes your character feel even more awesome in those situations where they they get to shine against raw damage, opens up the door to way more character customization without needing to worry about defense values, and just all around makes the game way more interesting to play than it previously had been. Should it be left in its current state? Absolutely not. It's completely overpowered and needs to be changed. However, I still think it deserves to be given a closer look before it gets patched into the state it was originally intended to release in.
Sorry for the long messages, I just genuinely enjoy this perk and wanted to explain my personal view on it to SoAndSo before any plans were put into action.