there could be different kinds of villagers eg
dyer: it could charge you to dye clay, armour for u and you could buy dyes.
Smith: it could make specific weapons for u, either for a fee of emeralds or other objects.
Messenger: if playing multiplayer, you could pay him to send a message to another player.
Hunter: you could hire him to either go hunt with you or for you, but you would need to tell him what to hunt for u.
PS: this would require a new villager interface:)