It would be still be somewhat difficult to mod their damage under this circumstance, but you will be able to set the spawn period, chance, type, and count. (Thereby making it harder/easier depending on the number rather than regional damage settings). The reason modding damage by area is hard is that the plugin is currently coded to simply draw the damage of a mob from a list of mob types when the event fires, and the individual mobs have no method of any sort to track their damage dealing. Checking regions would complicate this process a LOT, probably beyond that already used to store hp. On top of that, the region data would have to be stored in a separate container class, which also needs a linking method to specific region names. It would be possible, but a huge mess. With bonus spawns, even extreme armies are possible. I was on a server the other day which had over 3000 zombies spawned with no lag chasing players around. This is why I'm not too worried about people needing to buff mobs in a region, they can just spawn more and get the same effect but with more atmosphere.