Ok, I know this is do able with sequential spawning, but adding it in as a feature might help out the not so familiar people with it.
The Idea with this would be, the more you kill on the spawner, the higher the max spawns goes.
Example, start with 3 skeletons max. kill off the three, the max spawn increases by a % or a set #. So now you have say 5 skeletons on the next spawn, and so on. would also be nice for those spawns with the really good loot that people like to camp. kill off one hard ass monster and grab the loot, then wait for the respawn and *BAM* there's 3 of em this time.
It could use a despawn time to slowly float back down to the original.
Just a thought.
yeah, this is a straightforward sequential spawning scenario. I dont see an additional feature being added to do this.