The idea of villager trade seem to be usefull but many people have come to the realization that they are too overpowered and take many vital components from the game. The NoVillagerTrade plugin ensures that no villagers can be traded with. The idea of no villagers has spread ever since the 13 million subscriber, Minecraft Youtuber "Dream" made it a rule on his server with many other popular youtubers, such as "Vikkstar" and "Tommyinnit" I think many people would love to see the addition of this plugin into the game. Hope you make a decision on this suggestion!
Plugin Link: https://dev.bukkit.org/projects/novillagertrade