So I went back and tried the quest a few times. But there's nothing interesting about it. Kill someone. Listen to what other people thought of them. Kill another person. Here their opinion and what they think of other people. Kill another person etc. until there's one left, and they turn on you or think there's someone else in the house. If your disposition is high enough, the last of the 2 remaining people might think the other is the murderer and kill them for you, and I managed to get a girl to go into the cellar, but that was the best I worked out. I thought maybe you could twist their thoughts through dialogue or something but the choices are mostly limited to asking what they think about other characters.
So what's the huge appeal?
EDIT: Oh, and all of them ended up with Dwarven arrows through their heads and I'm the only one walking around with some kind of weapon (a dwarven bow and arrows no less) and nobody seems to notice.