Something that is on my mind since i first have seen those emitters.
The waves of Creeper are influenced by them, so why not have some fancy options?
Some are just classic CW options, some are inspired by PF intelligent particle behaviour and some are new 3d possibilities.
Amount: Creeper emitted per minute
Pulse: numbers of gulps emitted per minute
Direction: part heading and angle
Strength: 'speed' emitted Creeper has
Dynamic: emitter is intelligent and turns towards player units nearby
Alarmed: attacked emitter gains some kind of buff (hardcoded or tweakable)
Shielded: forcefield to keep an amount of Creeper nearby
For example this could be used to create a 'spitter' that is a Creeper mortar like emitter.
Low pulse combined with big strenght and dynamic direction. :o
This sounds like all of it should be a/many 4PRL commands. But, for non-coders, it would be nice to have 'em already built in the thumper/emitter.