ORIGINAL: MartialDoctor
Spying is overpowered to me in that it seems far too easy to get spies up to high levels with little to keep you from being successful. I'm not positive but I believe the main issue is simply that the AI doesn't have enough spies on counter spying missions. Either that or the counter spying isn't as productive as it should be and the enemy is constantly spying on me without me knowing. Although I think it's most likely the former as I catch spies every now and then yet rarely get my spies caught. At one point I had a particular race catch two of my spies almost immediately, so that seems to validate that (they must have had a spy or two on counter spying). So, this is one of those aspects I'd like to see addressed in the near future.
In my current game, I have 3 spies at level 400 with a few others in the 200 range. I use the higher level ones for deep cover or tech stealing. The lower ones are always going around sabotaging, stealing, and counter spying.
This could very well be part of the problem for the AI? I notice however that since most of my spy's are engaged in Counter Spy missions, I grab one to three of the bad guys spying on a regular basis trying to mostly steal my tech! I usually catch them as well, this is with say mid level spies and with around three of them working Counter ops[;)]