I like the tension that results from the game’s system. Not feeding leads to more power and less humanity, while the monstrous act of feeding makes the vampire appear and feel more like a mortal. Sadly the Stage 4 hostility is gone with Dawnguard, but I don’t let my vampires make trades or have important quest interactions with mortals unless they have recently fed. So mine feed to pass as mortals and also in Nivoniel’s case to recapture what she felt before she turned. Niv cured herself as soon as she learned how. (And then died. For keeps.)
I have a vampire who lives in a blood-starved state because she doesn’t want to feed. She wears a cowl with a mask to conceal her yucky features. I think DE’s idea that the prolonged hunger would cause insanity is a good one. It would inject some conflict into Venja’s life and make her a lot more interesting. Or it might cause her to jump into a volcano. You know, since taking a long sunlit walk is no longer the way to end it all. Venja has never heard anyone mention a cure.
My other vampire Selvyn (also deceased) fed because he liked it. He did not intend to become a vampire. It was kind of an impulse decision when a vampire suggested he never needed to fear death again. He thought being a vampire would be gross but worth it. Once turned he discovered that his tastes had changed. Gross did not have the same meaning. And also being fearless in the face of death does nothing to prevent it. Oops.
So Niv fed to keep her mortal feelings, Venja might feed to retain her sanity, and Selvyn fed because blood was his chocolate. Hope that helps.