Make a new rule titled “Mystic”, reading:

If there is currently no Mystic, the Mayor shall select one living, Non-Werewolf villager by whatever method e chooses. The selected villager becomes the Mystic, and the Mayor shall notify them of their new status. The status of Mystic is not an occupation and, therefore, not tracked in the GNDT. 
The Mystic should immediately contact each dead villager upon becoming the Mystic, and should immediatly contact each newly dead villager upon their death. Should any dead villager doubt the truthfulness of any communication claiming to be from the Mystic, e may contact the Mayor and ask for a confirmation of the identity of the Mystic.

Change the rule “Dead Men Tell No Tales” from:

A Dead Villager, except for the Mayor, may not reveal any information that he learned, made up, or other wise acquired about another villager, or any relevant information about himself that was not revealed before he became dead. This includes, but is not limited to, whether or not he or another villager was or is a werewolf; what another villager may have told him through private conversation; or even logical deduction about the roles of the other players based on the circumstances of the game.

to read:

A Dead Villager, except for the Mayor, may not reveal any information that he learned, made up, or other wise acquired about another villager, or any relevant information about himself that was not revealed before he became dead. This includes, but is not limited to, whether or not he or another villager was or is a werewolf; what another villager may have told him through private conversation; or even logical deduction about the roles of the other players based on the circumstances of the game.

However, this restriction does not apply to private communication between a dead Villager and the Mystic, or private communication between dead villagers.

This proposal is intended to give the dead something to do in-game, without involving too much effort on the part of the other Villagers.