Well as it stands now, a good civ could create the prophecy, take the initial 5 point hit, if there even is one, and then dedicate the city to building only buildings or research and money, but no units.
Perhaps instead of all units being created in the city baring the prophecy mark, why not have it randomly, or every few turns, spawn a special prophecy unit. preferably a little guy with one of those wearable billboard signs that says" repent, the end is near"
Perhaps instead of all units being created in the city baring the prophecy mark, why not have it randomly, or every few turns, spawn a special prophecy unit. preferably a little guy with one of those wearable billboard signs that says" repent, the end is near"