I agree with
@Hinin, there should be a balance of passive/active effects on spies. I don't like that the current system a) doesn't really hurt the host civ for your spies, except in very specific, military goals, and that 1 production sabotage option. b) i don't feel the success and speed of spy actions are tangible or accessible. Whether something succeeds or fails is a bit of a black box to me.
I think adding some more passive play to spies is also a great way to get at
@Milae's point about Tourism. Influence levels could increase the power of passive spy actions.
Example:
You have a spy that you send to an enemy city, you are prompted on its arrival:
- Embed in the scientific community (siphons 3Science, and an additional 3% per turn per influence level with the target civilization per turn from the city)
- Embed in the marketplace (siphons 5Gold / 3% per turn per influence level)
- Embed in the arts community (siphons 2Science/ 3% per turn per influence level)
- Embed with the tradesmen's guild (siphons 3 prod/ 3% per turn per influence level)
Then unlocked via some wonder or belief
- Embed with the local cooperative (siphons 5 food/ 2% per turn per influence level)
- Embed with the clergy (siphons 3Faith / +5% per Influence level)
Then Constabularies/police stations in the city could give a flat -25% modifier after the yield siphon is calculated.
So with good
influence your spies could deliver a pretty nasty per turn yield debuff to a given city's economy (- 3/6/9/12 % before reductions from anti-spy buildings), depending on influence level. In a standard game you could have multiple spies in a given city, decreasing different yields, or stacking their siphons, and crippling a leader's main cities. England could start with 1 spy, and they operate at 1 influence level higher, capping at 15% yields.
Then move advanced actions to a Great Spy that you move around the map like a GProphet to perform advanced actions on target cities. We could just implement a modified form of
Tomatekh's Great Spies, and give him credit for that module, since any advanced spy action system would just be reinventing the wheel.