In an effort to reduce "eggplantyness", I felt this suggestion was viable for consideration.
They have a plugin that enables mobs of like types (zombies - zombies, skeletons - skeletons) to stack ontop of each other. Not literally but for example from a 16 zombie spawner set up; instead of seeing 75 zombies in 5mins, you will see 8 zombies with name tags such as "zombie x10, zombie x5."
From what I know this plugin reduces lag because literally the mobs shown are reduced. (cannot identify they name of the plugin / any specifics as unfortunately I am not a developer). But if it has the potential to help the server, why not bring it to the table, right?