I would be tempted to have players invest in pools for "raw espionage" that can be allocated/spent sort-of like poker bets / silent auctions to affect situations and have the game provide a post-hoc narrative that fits the circumstance and result.Add thought... If I were building espionage (or an espionage mod) I think my overall philosophy would be "seizing opportunities," not "dirty tricks." I think I would focus on three areas:
- Intelligence: Build the game mechanics so that players can use better information to make better decisions, then use espionage to give them that information.
For example, making it possible to give someone a better offer than their current trade deals so that you can steal commercial/research/defensive pacts from other empires. Or making movement somewhat easier so that you can capitalize on learning the hidden locations of their shipyards, trade ports and anchorages.
Or, right now a balanced fleet generally beats all others. Tweak ships so that there really is no such thing as a balanced fleet, so that by learning the enemy's ship schematics I can crush them with a fleet half their size.
- Attacker benefits. Strategically, getting a benefit is the same as causing equivalent amount of harm without the trolling feel.
Let me siphon trade, research and production so that my espionage empire grows and thrives by stealing the work of others. Instead of sabotaging things, give me an entire set of operations that let me target specific planets and star bases for infiltration, boosting my income by X% of the target's production. Co-Opt Labs might give me a percentage of a planet's research, while Cut A Deal might give me a percentage of all trade passing through a starbase.
This could even add room for some more sophisticated defense gameplay. Players could get leaders that are better at counterintelligence, or some planetary decisions on the subject, so they can decide which parts of their empire make for the most tempting targets.
- Mistakes. Build the few negative operations around capitalizing on an opponent's mistakes, so that espionage attacks still connect with strategic decisions.
I'd keep some offensive-style operations, but I would design them around taking advantage of an opponent's mistakes or giving already-failing systems a nudge over the edge. The ideal operation would be largely meaningless in most contexts, but potentially critical when used exactly right.
For example, like we mentioned above, maybe an operation that lets you flip on an enemy's FTL inhibitor for 10 critical days. Or another that lets you shave 5 points off a planet's stability. These are meaningless on their own, but if I make the mistake of stacking all my ships in one system or letting a planet get too close to rebellion these operations could be devastating.
As the attacker it would give you a powerful tool, because everybody makes mistakes. The key is just being patient and observant enough to seize the opportunity when it arises (which is where good intelligence comes in). As the defender, I would still be able to see the strategic decisions I made which left me vulnerable to that attack.
Idk... I think that's where I would take it, personally. But again, this is all just speculation. If it was that easy to do I suspect someone would have already done this right in at least one 4X game somewhere.
Invading a colony? How much intelligence are you investing? How much is the defender investing? If you outspend him significantly, you cut-off armies in the field (forcing them into disengagement) or getting a few rounds of attacks without counter fire. If he outspends you, he can do the same or lay the groundwork for a long term guerilla engagement.
Attacking a station? If you outbid your opponent, one or more systems may fail to function because of covert ops against them. If your opponent outbids you, he knew you were coming and all systems are hot and get to fire extra-early.
The system prevents passivity on defenders and those that get slammed know why they got slammed.
The way to avoid pile-ons wiping someone out is to make stockpiles affect a single nation only (so you need a lot of different stockpiles) while at the same time making adding to a stockpile non-linear in cost so a big stockpile costs an awful lot more than one half its size. Or have a single stockpile but have individual bets become non-linear in cost.