Probably the way the fights go. Every nation has the ability to build large and powerful armies, and the outcome of a few of these large battles will ultimately determine the course of events. Also the way the financial system has been reworked. With the constant wars I am fighting I have to make crucial decisions on where my money will be spent and how, as well as whether it is more to my benefit to exterminate a city for quick cash or to retain it to provide a powerful economic center.