Yea, a military advisor patch. Read the threads on different forums. It is time for a LOT of patches.
Espionage??
First you have to spend your time and money building the espionage advance.
Then you have to spend more building the Intelligence Agency Small Wonder.
Then you have to spend still more ATTEMPTING to plant a spy; if caught you have an international incident.
After all that, you have gained nothing except a hole in your treasury, and one less useful advance.
You then have the privelege of attempting to use that spy for something - and to do so at an EXORBITANT cost. Again, if caught (a real good chance) the money is down the drain and there's an incident. You can't even use the spy for propaganda against Democracies, the most common government when Espionage is available.
Espionage is not cost-effective. Go build yourself a more useful advance and a better wonder along with a whole bunch of tanks instead.
PATCH: Make espionage much less costly with less of a chance of failure. I once went twelve times in a row (in different games) trying to expose a mole at the "Safe" level and every time MY spy was caught!! No thanks, Sid.