I'm on board minus the murderer trait. Speaking just for myself, such things are fun when made into mods, but for regular Sims content would be pretty jarring. That and of course EA would never approve of such a thing, I can't think of anyway they could add a "murderer" trait and tone it down enough to fit the "family friendly", super sanitized and (IMHO) super boring and squeaky clean image for the game they're promoting as of late. Still, fun idea for a pack, I've wanted more criminal gameplay features since they were added in GTW, lol.
As for crimes, I'd LOVE if arson was added, but again, I doubt EA would go for it. Just imagine Sims setting fire to buildings or objects then trying to flee before being caught by the cops (or a vigilante or even a well-intentioned busy-body with nothing better to do). It'd also be a great excuse to fine-tune and add more functionality to the klepto trait!