There are many fun quests that tell about minor factions and different pops and major factions quests that reveal their lore. But i think a very important element is lacking. Quests that feature interactions between two particular Major Factions would be a great way to make the world of Endless Space more alive, i am sure.

There is no need for 28 (number of pairs formed from two different Factions) complex relations. But at least some seem very needed to me. Also, mirror interactions (f.e, two Horatio empires trying to prove themselves the true one) would be fun.

Some examples:

1. Vodyani and Cravers are both creations of the Virtual. Wonder what Vodyani think of this fact.

2. The Heart that the Unfallen worship is considered a demonic force by the Vodyani. Maybe there could be a quest inviting Vodyani to somehow hurt the Unfallen for a reward.

3. Horatio Prime was once a citizen of UE, but wasn't warmly welcomed. 

Does he find them (or maybe the strange otherworldly anti-ecologist Riftborn) especially ugly? Maybe he is a bit friendler to the Unfallen, as an ecologist? Horatios could get quest rewards for waging war against a particular foe or befriending the not-so-ugly (only to ease the beautification by this alliance, of course).

4. I think Sophons just can't be indiffirent to the marvelous Riftborn. If i was a Sophon, i would do anything to be able to study a Riftborn, would it be diplomacy or brute force.