I have mixed feelings about invaders. On one hand, I like goblin invasions, because I can loot their equipment for iron, and also because I can try various fun tactics (e.g. cages). On the other hand, I hate werecreature invasions - no loot, and messy to deal with.
I can disable invasions entirely using dfhack, but I cannot do it selectively - what I would like to do is enable only the goblin invasions.
So my idea is to implement some universal tactic on werecreatures - kill them in some easy, safe and uninteresting manner. For that, I want to predict where they will appear, and then arrange obstacles in some way, so they will be unable to attack my fortress, and could be smashed easily, e.g. using a drawbridge.
So, how can I predict where they will appear? So far, I have seen them appear only on the surface, and always outside my fortress, but always close enough so I had no time to pull a lever - while goblins always appear near map edge, where there is enough time to raise the drawbridge.