I think there's a balance to be had, for sure. That's why my current setup is to give you a "Blood Frenzy" buff when you first hit Starving, as a sort of crazed damage buff that eventually wears off. To get it again, you have to feed back up to Well Fed, so it shouldn't be easy to abuse.
Side note: I've been sidetracked by an ever-increasing amount of smaller QoL mods, so Vampirism has taken a bit of a backseat at the moment. With that said, I've learned a ton about how to script with the story editor, so I'm in a better place to rewrite Vampirism's scripts to be more mod-compatible.
