Well heres an idea, howabout instead of having the father get the necromancer trait cause his children died, have a child get that trait when he comes to age IF AND ONLY IF his father has passed away, and maybe one more family member etc.

How would that stack up to game mechanics? The idea of having the trait increase the chance of casualties recover does sound REALLY interesting :D
and could be used in the undead factions instead of healers and stuff like that.

On the human side, It would most likely lead to attributes like bodyguards like mentioned earlier.

What if lower piety meant less public order? The necromancer trait could lead to the general have less piety. If you could tie in piety with public order or traits that decrease public order you could simulate how the populace would feel towards an INFIDEL that uses necromancy while under sigmar's dominion or other dieties.

Cheers :D