I was using espionage quite a bit in my first few games, but in my last two I have not used it at all. The main reason I was using espionage was to determine the tech areas of my AI opponents. BUT, it seems I can do this much easier with 100% accuracy for free by just going into the "Speak To" screen and scanning their techs they have for "trade". :-/
It then occurred to me that perhaps the AI would simply not display techs that it had, yet was unwilling to trade. But, it seems that there are quite a few things the AI has displayed on the "Speak To" screen that it will not trade regardless of the offer...
This stirs a few other points/questions I had regarding the trade screen:
1.) The AI seems to value its Colonies, star bases and ships VERY, VERY highly while it places very, very little value on the player's colonies, etc. I suspect this is required or else the human player could find many a loop hole to screw the AI in these types of trades (ex like right before declaring war on the same AI race).
2.) The AI seems to value its votes in the Galactic Assembly VERY, VERY highly while it places a very low value you the player's votes. I see no real reason for esp. when the player has no idea what is coming up for vote during the next consol session (or do we?) and the "trading" of Galactic Assembly votes should be the most common type of diplomatic trade (IMO).
3.) The AI does not seem to do much tech trading amongst itself much at all.
4.) I see no way to ask/demand an allied race to attack someone I am at war with as they do not appear the poplist on the trade screen (or is this because my ally is "friendly" with the folks I want them to attack and am at war with).
Later,
GG