You mean
Draugr?
Protip: Burn your dead, on a funeral barge. Or invest a buggerton of points into wrestling skills.
While I don't feel a world ending event with hordes of walking corpses would be much fun, since basicly anyone without a palisade would be buggered right off the bat and it'd be unfair to new players, I do feel it'd be neat if unburied dead started haunting the battlefield. (Maybe not so much fun when your newly claimed gold mine is jam packed with ghosts & ghouls but eh, I'm not a PvP fan, what would I know.) Obviously to prevent intentional slayings of alts to create cheap watchdogs and weird undead cults it should be a relatively low per-centage that actually rise again if unclaimed.