I thing I liked about GC II is that you can demand empire A to make peace with another empire B. If I'm in an alliance with empire B, this was a handy tool to end wars that I wanted to stop or be dragged into.
I haven't found the ability to do this in GC III, from what I could find. Perhaps some some diplomacy based technology makes that possible? If this is not a feature available in GC III, perhaps it could be added in the future?
