Agreed, i can understand why people who enter cities don't want vampires to spawn somewhere else in the city that isn't the front. I'm sure that's a bug if that is happening to people.
HOWEVER, that doesn't mean the attacks on towns/cities should be removed in the next patch by Beth. And that also doesn't mean that permant NPC's death should be removed as well. Because it seems that many people here think that to fix this event is to remove the attacks on towns/cities and to make NPC's, even important ones, to be able to come back after death (repopulation idea), or just not be able to die (which would make the vampire attacks pointless).
Let me clarify this situation: It doesn't matter where the vampires spawn. They will initiate combat the instant the cell is loaded and go after the nearest actor, usually a wandering NPC. Given that they pretty much one hit a regular NPC, I very much doubt that the player will be able to get there before that NPC dies (Unless the player knows what's going to appear in the cell before it actually loads, which is impossible). And now the player will have to reload another 5 times just to keep one stupid NPC alive, and then, finally, you save him. Was that fun? I didn't think so.
And sometimes in walled cities, an attack will occur with the player unaware (usually the player is on one side of the town and the vampires on the other). Later the player visits that part of the city and finds it has been turned into a graveyard. Does the player have a save to revert to? Maybe, but I wouldn't count on them doing it if they'll lose 30+ minutes of gameplay.
And now players everywhere have to search the entire town everytime they enter/exit a building just to be sure there are no fights going on. And if there is, another 5 boring reloads. Then you exit the city, and possibly find the stables under attack. Cue another 5 reloads. But what if the player hasn't saved for a long time? Do you really expect them to willingly lose 15+ minutes of arduous gameplay?
And look at this thread, if you have time:
http://www.gamesas.com/topic/1391660-riften-massacre-master-vampire-attacks-imgs/
This guy plays on master difficulty, where NPCs are more resilient than usual. But that didn't help one bit and the NPCs still got massacred, as you'll notice if you look at the pictures.
And what of wandering the wilderness? The player wanders near the unwalled city of Falkreath. But that's enough for the cell to be loaded. And it's possible there could be an attack or two in Falkreath and you have no knowledge of it. Oh, except when you go back to Falkreath later and find dead bodies all over the place. You could go back to a previous save, but it's been a long time since then, and unfortunately, you've overwritten your save. Repeat this for another few unwalled cities and they will soon become ghost towns.
So let's recap: To save a walled city from certain destruction, you have to search every square inch of ground everytime you enter/exit a building in the city, in-case there are any fights/dead bodies. And that's just being lucky, because attacks can occur without the player's knowledge. Unwalled cities are even worse off, because the player just needs to be near the city for the attacks to occur.
And the solution to this extremely hard work? Remove the attacks from cities. Problem solved.