Most things in life aren't black-and-white, sometimes you need a shade of gray in between. Now instead of entirely disabling mob-spawns, you can adjust the rates in certain areas. The "factor" parameter of DMZs will alter the vanilla spawn rates, with "0" being fully disabled and "1" being fully vanilla.
I've also cleaned up the config a bunch. This was one of (if not the first?) plugin I made, and the config file was a disaster--requiring every mob being present in the config.
This version does have a slightly new config format. Take note of your existing DMZs and then re-gen the config by deleting config.yml. One day I'll make updates more graceful, but today is not that day.
Paired with this is a significant cleanup of the code that should make this plugin even more lightweight than it was prior.