Forgive my ignorance, but doesn't Argus sound a lot like Pariphaistes but with cost over build times? I think if new (exclusive) heroes are to be added for all/most of the events, maybe a contest is in order to choose the effects.
Or give us the option for duplicate heroes. Who wouldn't want Demo, Orpheus or Deimos in 2 cities? They seem to be repetitive anyway, just not as good as the original. I don't know, just a thought.