It isn't fair to say things are useless if you have won the game already. Also one thing about corporations that I found is that they are insanely profitable. I read sid's sushi article and in it he says that spreading the corp costs 22 gold per turn upkeep (in the sample game he was using). In my experience I was spreading sushi for an upkeep of 7gpt and mining for 10gpt. But my wallstreet/HQ city was turning all those 4gpt incomes into 12gpt. So each branch I made earned me profit rather than a slight loss. My HQ city was making SO MUCH GOLD! The main problem the OP has with spies is he just isn't using them right. You are trying to make them do things they aren't supposed to do (wound units/flip cities). I know in Civ II "incite revolt" simply purchased the city. It does something totally different here. You can also send in spies a few turns before declaring and place them on all the copper/iron/coal/oil and then on the turn of declaration you destroy all their access. Obviously stealing tech is useless if you are ahead, but if you are not ahead it's far from useless. I haven't really messed around much with poisoning water supply and fermenting unhappiness but I am sure heavy use of that could slow an empire way down. Spies are cheap enough to be made in your low hammer cities after they have build all their useful buildings and you can just camp them about. Also you mention that most of the uses of passive espionage can be accomplished with sharing a religion? Although in Warlords and Vanilla you could investigate cities that shared your religion IF YOU ARE THE FOUNDER, that is no longer the case in bts. The passive benefits of espionage are very useful and the only way to investigate the cities.