The problems with making diplomacy and diplomatic victory rely on winning the hearts and souls of people are the following: firstly it is too much like a cultural / influence victory and it doesn't have enough of a diplomatic flair to it, secondly it doesn't work entirely in a setting marked by vast differences between species. How does one go about becoming popular among Cravers? They have no individuality and are a hive mind, save for those infected by dust, and they are too hungry to care. What about factions like the Sowers or Harmony that are obsessed with one goal? I would find it bizarre for one to become popular with Harmony while still using dust.



I believe diplomatic victory should definitely have a cultural facet, but I think it needs to be institutional as well. In Nobunaga's Ambition: Sphere of Influence, one could win a diplomatic victory by becoming Shogun and then passing a law banning warfare. Now while this is too easy, I think ES2 can be inspired by the concept.



What if diplomatic victory leads one to the route of first establishing a Galactic Council (needs at least 3 founders), and slowly but surely increasing the legitimacy of the institution in the public mind through passing laws, inviting new members, regulating violence (banning certain weapons / tactics), providing aid (players can decide how much dust they want to devote. Those who don't devote anything at all would lose legitimacy in the eyes of their people), and brokering ceasefires and peace. And as the Galactic Council becomes more and more legitimate, so too would the influence cost of defying it increase. Only someone who has massive influence and massive popularity can defy the council without much repercussions, other than a diplomatic fallout with the others.

All this would ultimately culminate into the banning of warfare, and thus a diplomatic victory.



I think such mechanic would combine both popularity and influence among the public, with the political negotiations that need to exist for it to feel like diplomacy. And in such an arrangement, I can see factions like the Sowers and Harmony cooperating, not out of public pressure, but out of institutional pressure.



Of course the anomaly will always be the Cravers, but that's fine. Perhaps one of the acts a Galactic Council can pass is the creation of a coalition against the Cravers, as a "rogue state." It would also add a cool gameplay feature of the Cravers, in that they could never be part of the Galactic Council, which on one hand frees them from all obligations and allows them to do as they please without cost, but it would increase the risk of coalitions forming against them as it should be.