[Alneyan]

And even without consider trade with this Dishonourable Foe, you will need freighters within your own systems, if only to bring food to this industrial world of yours. Humans being what they are, the Dishonourable Foe might try to corrupt a captain or three of such ships, thus allowing for potential spies to make it to your planets.

And then I do like Scout's suggestion: it should be harder to strike a race with a mere planet and two ships than an Empire ruling over a thousand worlds. And the more attacks you launch, the more prepared your opponents would be, especially against the same planet. You would expect a planet who has just suffered from a catastrophic plague because of some operative to be much more cautious, wouldn't you?

What I would like as well would be to have actual operatives to perform these projects. You might try to have a few, very talented agents, able to succeed much more easily than your average Joe, or a lot of beginner agents, or an elite team dedicated to Counter-Intelligence, or some Jack-of-all-trades and so on. Something along these lines was done for Imperium Galactica, and was probably one of the few good ideas in this game.