Since Mila has an in-game fetish for vampires and fantasizes about being fucked by a vampire, it means that Bianca is actually the perfect partner for her, since Bianca has no desire to drink blood or harm people. Mila could have her fantasy, without any negative consequences.
Also, I hope we get more story with that succubus, either in this game, or a sequel (or both).
Another thing I'd like to see, is a Nosferatu Queen, a stronger version who still has her intelligence intact, and her own bad end scene.