ironically i think Necromancer would be a better role for killers,
If they can listen to ghosts they'd be able to get information on crew members by the ghosts, if a killer is dead they could follow someone and tell the necromancer when they're alone and coordinate the sabotages better.
It would also make it easier for riddle killers too, as ghosts might tell what roles they think people are and the necromancer would have to give this information to the riddle killer without being too obviouse.
or you could take away their ability to kill by themselves, but be able to revive dead killers between meetings. (they'd have to go to where the killer got eliminated and have a cast time so people could see them reviving a killer.) (a revived killer doesn't add to the number of killers left, so you can't revive a killer and suddenly win by outnumbering.)
here's how revived killers would work is, they have a small time limit to kill someone. once that timelimit is reached they get eliminated, once they kill someone they get eliminated and if a meeting is called they get eliminated.
This would work well for players too, since revived killers wouldn't go after killer players and players know that a revived person is a killer, meaning killers have to be careful who they chase and where they go, since if they go after someone but not another it would make that person look suspicious.
It would also help give dead killers more to do once dead since just sabataging isn't the most engaging.
