I would really love to see a couple of diplomacy options added, such as:

1.  Being able to attack another faction even though you have an alliance with them.  I've noticed that some of my allies have begun to ignore my existence and moved onto other threats.  I would really like to take advantage with a suprise attack.

2. Being able to negotiate a truce between two warring factions, i have seen it in other games and cant see why it wouldnt be included here.

Im sure other people have ideas for diplomacy options, if you do, post them below .

By the way,  I love the game, good work Stardock.