I've noticed something very irritating of late. When ever I go to war with a civ, come time for the peace treaty they are almost always running low on gold and gpt, and since I embrace the rogue state theory, they rarely have a tech. No problem though, they have plenty of lux's and resources, that should be perfect! But no, the game wont let me trade luxuries or resources as part of a peace treaty. Why is that, and is there some way to make it possible?