So I've been thinking of a compromise Bethesda could do to sate those who hate the attacks and those who appreciate or like them. Instead of having Vampire Masters no matter what level you are, the vampire attacks should be appropriate for your level. So for instance, if you were level 50 or higher you'd naturally get ONE Vampire Master, a thrall and maybe another weaker vampire. If you were level 10, maybe a thrall and two weak vampires could appear. And maybe for blood hounds, perhaps only one and a weak one.

Keep in mind, this is not a perfect fix, rather is eases the problems of vampire attacks somewhat. The guards will most likely take them out before the vampires can start to attack the citizens and if they do, another guard will take his or her place and of course youll be there more than likely.

Thing is, the attacks already do seem to be scaled to your level. The "Master Vampire" NPC gets scaled to your character's level, and can range between level 14 (for character levels 1-20) through level 42 (for characters level 31 and up). This level scaling probably accounts for why the vampire attacks are so much more devastating for higher level characters than for lower level characters; a couple of guards can quickly dispatch a level 14 attacker, whereas a level 42 can survive for quite a while against a group of guards while easily one- or two-shotting almost any citizen they come across. Of course, higher level dragons can also take out ordinary citizens easily, but don't attack nearly as quickly as the vampires can; hence why higher level players seem to encounter such difficulty in preventing vampires from killing off citizens (since the vampires can wipe out multiple citizens before the player can even reach them).