I play A LOT of crimcorps (arguably the empire that most makes use of espionage) of all flavours and actually engage with espionage quite a lot, both vs AI and vs real players.
I actually really like a lot of how the espionage system already works, very passive but it could be more easily accessible/obviously accessible or at the very least demand SOME sort of attention for YOU to DO something rather than you having to seek it out through the empire contact screens.
I like a lot of the operations already, decently impactful without feeling oppressive to be on the receiving end of. I would either trim/merge the useless stuff and add some brand new stuff, or buff some of the existing stuff to be practically brand new, or all of that?
Gather intelligence; for a crimcorp? great stuff.. after the 'trust' rework this is the easiest way for me to find enemy empire worlds to slap down branch offices ASAP. getting 30-60 intel is quicker than getting the trust to build pacts and opinion. for any other empire? useless. other empires need a reason to use it, also it loses its usefulness quickly by mid game.
spark diplo incident; seems to be useless unless you play on a tiny, curated galaxy of 3-4 curated empires.. needs to be more 'targetable'.
sleeper cells; good stuff, lock in your intel for 15 years (maybe make this longer?) so you can move your limited envoys off to do something else. could just get rid of this entirely and just always keep your intel?
acquire asset; eh.. useful, could be better. needs to be more 'targetable' (need to be able to pick what you want. not just get given a random one). i would actually merge this and gather info together. assets already passively buff intel gathering.. just merge them, make it the first in the tree, need some 'unique' assets in the same vain as 'unique' paragon leaders, etc. maybe you could roll a saboteur that doesn't just destroy one starbase module, but 2 or 3, etc.
extort favours; after the empire p2p trade rework no longer being able to trade favours, and favours naturally being much harder to come by without sinking into a whole tradition tree or 3, i like this one. i'd leave this completely untouched
smear campaign; same as diplo incident, useless unless using a curated galaxy. needs to be more targetable and spammable to begin with. would probably just merge with diplo incident tbh, make it more powerful, make it more expensive
steal tech; awesome operation. wouldnt change much about it, maybe make it a little more 'targetable'? if the target has nothing to steal maybe make the resources scale instead of a flat 1000 per branch?
sabotage starbase; has won me like 2 multiplayer games by itself, but highly situational. i've used it to destroy cloaking detection modules on enemy multiplayer detection starbases to enable me to juuuust jump my cloaked corvettes and frigates undetected into their space for first war strikes. other than that? completely useless. needs to be more targetable
arm pirates; has indirectly won me a few AI and multiplayer games, purely by chance though. spawned in at a key chokepoint in a far flung system at just the right time cutting off trade. needs to be more targetable rather than basically spawning into a random system, needs to 'scale' higher now that the power scale of the game has grown so much. i would just merge this and sabotage starbase and call it 'raiding party'.
crisis beacon; dont have much experience with this one tbh, very limited window of time to use it?
emperor operations; all pretty much useless because having a bigger fleet matters the most
consume star; i love this one, powerful operation for defeating a powerful leviathan. i always charge for the stellarite devourer purely for this operation. we need more 'special' operations like this.
lure the kaleidoscope; i like this one too, but this one needs to present itself to you if/when the event occurs. you're too busy dealing with -2000% resources, -50% energy income to go and worry about spying on someone.
some things you could add; need some more operations that interact with more dlc. if utopia is installed; target mega/kilostructures/hyperlanes/gateways. if paragons is installed; target planetary officials and government leaders (scientists and commanders are already killable). if first contact is installed; something to buff your own cloaking against a target. maybe a way to falsify your fleet/starbase/econ/tech power to another empire? ethics based operations?
we also need more influence storage OR espionage could buff influence generation somehow OR espionage could just not cost influence at all? because taking as much space as you possibly can and using all of your influence for that through expansion and claims is still far more enticing than doing any of the above.