I haven't had any of these obnoxious incidents with vampires invading houses. They sometimes come visit at night with families who have friends/relations in the vampire world and/or who are raising young vampires. Most of them do not enter the house without permission. None have ever attacked any of my sims while NPCs. In fact, the only incidents I have had in my game with sim vampires attacking other sims without direction has been when they are in a very angry mood state. This has happened twice and in both cases the sim was one of my sims and they went and did it without direction against a close family member. In the case of the one vampire, he had a guilt fit afterwards and basically hid in his room for the next day because of it.
So I have no idea whether this is the lottery of the game, but I have about fifteen of my own vampires bred and there are at least ten or twelve NPC vampires lurking around and most of them you don't even know they are vampires unless you click on them to interact because they aren't doing anything obnoxious.
*shrug*
Maybe I'm just lucky...?
I think it would've been awesome to have a Vampire Hunter career path specifically though with the pack and the ability to create some kind of Vampire Human War.
