I hear a lot of good ideas. Was thinking how we could add them.
Rebellions, have noticed that there is no penalty for doing things outside your moral alignment. If you do that enough times some in your faction might feel you have lost your way, your not a true good, bad or pragmatic leader and they break off to form a more pure version?
The don't trade with that guy he is going to win. I was thinking we might see this when espionage added. Spies can often plant info, you should also have the ability to warn factions like they warn you.
Coalitions, EU games have it where when multiple nations go to war with others, the best/most powerful nation becomes the alliances lead faction. They set strategy for the war. In the game this could me, if your are lead, you could mark planets controlled by the enemy as planets to invade, defend. If your not, you might get missions from the lead faction, like please take planet x in 10 or more turns. When peace comes, the lead faction does the negotiations. This is neat, because if you hose your allies and keep all the planets for yourself you might find them turning on you. There is a historical president for this, many allied nations in WWI felt screwed at the peace table and turned in WWII, ie Italy and Japan were on the Allies side in WWI.