The targets not being in the same place everytime or changing their routes means you have to adapt new paths on the fly, which is a good thing right?
It really is. Of course, for a spawning system to really outlive a level's replayability I think the level itself needs to be fairly "big"- unless we're talking about a labyrinth kind of level, like a dence park or a well stuffed library. A museum would be awesome!! x)