I think espionage is such a difficult system to deal with because it is essentially tactical level play. People complain about warring and 1upt, and espionage essentially is an extension of that. I do generally feel there needs to be ways for Civs to play a bit underhanded, but the problem is, it's frustrating when it is used against the player. People only really want it to use against the AI. Espionage points was the right solution, but the implementation with spies was kind of shoehorned. I like high level stuff. You accure EP and can do operations to steal maps, and do minor sabotaging. Nothing too overpowered. but I suspect what we will get instead is a spy unit (agian) and a whole lot of balancing to sort of get it to work.