Seriously, the more I think about it the more the uselessness of spies becomes obvious. The limit of 2 actions per day offensively and defensively is artificial. The effects of almost all spy operations aren't worth the money you spend to use them. Gather Intel and Destroy Nuclear Weapons is about the only operations that are worth using. Gather Intel to check your enemy's warchest, and Destroy Nukes for obvious reasons.
There've been a lot of suggestions to make the other options more potent, which I strongly agree with. For example the change defcon and change government should let you choose what defcon level you want to set them at, or which government you wish to use. This would allow for targetted changing at critical times (for example a sledding target sitting at 19 days innactive being set to Defcon1 and changing government type to Anarchy can cause the opposing nation a lot of money)
The destructive actions all need to be buffed significantly to make them worth the investment. Destroying 1million dollars was a low limit when the spies were implemented, in todays day and age with billion dollar and more warchests, it's just a silly low amount. It should be something like 5% uncapped. Let those people with large warchests fear someone sending spies out to destroy their reserves. Same thing with destroying tanks etc, the amount destroyed is just too low to be worth anything to anyone. You can argue realism all you want, this is a balance issue of an option being useless. If you're going to make it useless to make things more realistic, just don't bother offering the option.
But these are things that have been covered by others extensively. So I'm going to go off on a bit of a different tack here and hope this catches a bit more favor.
You should get the ability to assign your spies. When you purchase your spies, for them to have any effect, you must send them to another nation, and that is where they're assigned to until you recall them. The initial deployment has a chance of being uncovered, but shouldn't be too hard to accomplish. Once spies are assigned, they must be recalled to be redeployed. After being recalled they cannot be redeployed until the following update.
Now while the spies are within the nation you have a passive gather intelligence effect. You can view the stockpiled money, standing military forces (speaking of that should be something else that is hidden without having spies deployed), etc.
Now here's the trick. Every deployed spy can get two spy actions off per day. Deployed spies do not count towards defense towards enemy infiltration and spy ops. This leaves you with a choice: Seek an advantage against enemies by deploying all spies against your enemy's nations, or keeping them at home to protect yourself against infiltration. Additionally the choice arises, do you send small groups of spies hoping the enemy has low defenses, or do you send all your spies to the one enemy you wish to keep the closest watch on? It gives a choice in strategy, which is sorely needed.
As an aside, you could also make a benefit for leaving untapped spies in place for extended periods of time. The longer a spy is undercover in his role the more believable the role is, the less likely he is to get caught. So say a passive scaling bonus to spy ops success rates the longer the spy stays there. So you're better off with spies deployed to a nation and keeping them there for months before they're actually needed to wreak havok than just sending them in and doing your spyop the same day.
Now like I was saying, every spy can get off two actions per day at most. When you declare an action you decide how many of your spies are working on that action. The more spies you use, the better the effect and the higher chance of success. However if you want to be a real risk taker you can take 500 different actions against someone, with 1 spy each. Just expect to fail with it.
Anytime an operation is failed there's a chance of cover being blown. If a spy's cover is blown and the sending nation is found out, all spies from that nation are sent back home, and the defender has a 25% bonus to defending against infiltration for the next week against that person. (or maybe 10% against all infiltration). So if you do infiltrate a nation with 500 spies and try to have them do one spyop at a time, the first one almost certainly fails and your effort is wasted. But having a handful of spy ops say 150 or so spies at a time will have a good chance at success, especially if the enemy has most of their spies deployed elsewhere. Or having the spies deployed to a handful of nations for 2 spyops each.
Or really under this system you could reduce it to one spyop per spy. It makes it easier to track in game and might help balance out the splitting up your spies for as many spyops as you're willing to risk.
Anyway, that's the general idea. It can be refined as needed, but the general concept of deploying spies for passive benefit and activating them for missions only after they're already there I feel is a good one.
