There's a lot of gamebreaking stuff like that. And instead of patching it, like any decent developer should, they make us do it ourselves.
Thank god for Timing Is Everything. I disabled vampire attacks entirely.
I'm actually working on a mod to improve vanilla vampires without breaking other vampire mods via an interesting mechanic: Parasitizing ancient vampires to steal their powers. They're boss battles where each ancient has its own signature power that it uses during the fight. Once you kill them you drain their blood and gain a new power.
I'm also thinking of adding a couple weaknesses as well. Weaknesses to things like garlic, piercing weapons, damage while in chapels, etc.