Strategus could have a "spy" system that might be interesting... It might go a little something like this:
You create spies (how? I dunno. We can think about it.)
You can drop these spies off wherever you like -- any village, town or castle, you can just leave a spy there.
Having a spy in a village gives you full visibility into that village, as if you were there. You can see who is in the town and what they are doing.
You can attach the spy to a player: 50% chance of success, 50% chance your spy is killed in the attempt. (If the player is recruiting then it's a 90% chance of success.)
If you have a spy attached to a player then you can always see him on the map and you can see the full details of his army -- his troop count, his weapons, his goods, his destination. If that player gets in a fight, your spy has an even chance of getting killed (if he lost half his army, your spy has a 50% chance of dying -- your spy is literally one of his troops). (Another idea: rather than full, constant visibility, you just get a button that says "Spy Report". Clicking this will give you a snapshot report at some risk to the spy.)
So the idea is you generate a stack of spies and then leave them scattered around and occasionally check in with them to see if there's anyone interesting to attach to.
Your own spies might also act as counter-agents, reducing the chances that anyone can attach to you as well as perhaps performing "sweeps", at some cost, with a chance to find enemy spies.
