I do not know wether or not this has been suggested before, but canabalism would be a lovely addition.
The magnificent aspect of Haven and Hearth is the need to use every peice of resource possible to survive and expand. Albeit I have never killed a person, so I am not sure if this is already implemented in the game, I know for certain one cannot use another's skeleton for their human bones (which should have some special necromantic value). To be able to eat anothers flesh for the +2 FEP gain of thier highest attribute would be great! And then the dishes one could create would be even more interesting.
While we are contemplating the subject, I might as well mention some other similar ideas. A skin suit would be even more useful. Not for any attribute bonus, but just to make one's trespassers deficate massonry. I would atleast settle for a skin mask.
Also, taking corpses and hanging them in trees to ward of tresspassers would be nice too. Nobody would raid my precious items if I had a few bodies hanging from my willow tree. If anybody is a fan of the creature 'Predator' (from the movie with the same name, the one with Arnold in it) and have played such games like 'Predator: Concrete Jungle' they would better understand what I am suggesting.
Also, when it comes to killing wrong doers, why cannot we behave more civilized? Forcing a convicted person to the guillotine and noose would be difficult to preform. But, a posse of well armed villagers forcing a convict to use the guillotine because he would loose more FEP with them just killing him regularly would be great! And the villagers can get some sort of 'civilized' bonus for their trouble.
Maybe by having the person in shakles, one may force them unto the execution method? Notice I slipped in the idea of shakles...
I believe these ideas would greatly serve to those in the pursuit of justice. And necromancy.