So pretty much half the fun of oblivion and fallout was going around and slaughtering all the nice folks that have only shown you kindness. How long after you have started the game will you start your genocidic rampage and how many people will fall victim to your malice
I see no point in this. Last time I killed a bunch if people was my first play of Morrowind and I didn't feel like accomplished anything. I didn't feel bad or anything, I just felt like I wasted my time. So I never did again in any game after that, elder scrolls or otherwise.
The challenge and fun comes from playing the game as the developers intended. NPC Slaughtering just isn't fun, rewarding or challenging.