I would want something along these lines:
WAR & PEACE (post-Utopia expansion)
- Super weapons. Exclusive unique doomsdayweapons and ship classes for militaristic and materialistic empires, including stealth ships, planet busters and the much dreaded Nova bombs!
- Revamped ground combat. Deeper land battles and planetary defenses being able to shoot down attacking fleets makes for a new dynamic interaction between ground and space combat!
- Reworked defensive systems. Introducing mega-fortresses, galactic geography, minefields, self-destructing stars and warp dissipators. Now terrain and position matters more than ever!
- Fleet formations. Change your combat stance mid-fight in order to change the course of battles. The more skilled your admiral, the more formations avaible and the less downtime to change your tactics!
- Attrition system. No more super stacks of doom. Win battles against superior enemy forces and fight guerrilla wars and skirmishes outside the open battlefields
- Sector governors and leader ambitions. Intra politics never were so tangled. Love stories, personal grudges, greed, envy, ruler lineages and special skills makes for a more dramatic and complex politics and better sector management
- Spyionage. Manipulate factions outside your empire, bring xeno leaders into your fold and play with their interest and desires in order to make your enemies crumble from within. Comes with its own "secrecy" tradition tree, too!
- From confederations to federations to actual unified star nations. New and improved systems for nation building and more diplomatic venues for cooperation, including secret pacts, research treaties and much more!!
- Introducing the galactic senate. Build a harmonious new galactic order, instaurate a despotic pan-galactic hegemon or fight for your independence against foreign influence!
- Separatist factions, civil wars, rogue hiveminds and revolutions will provide new challenges and opportunities for galactic empire builders
- New victory conditions. Win either trought military might, peaceful federation building or ascension!
TOWARDS A GLORIOUS FUTURE (long term, post-post Utopia expansion)
- Expanded tech and civics trees enlarges the game's scope and late game like never before!
- New ethos-specific winning conditions. Experience special endgame crisis and ascension paths beyond the materialist - spiritualist axis. Treathen to activate ancient weapons of mass destruction as a xenophobe, build a post-scarcity economy as an egalitarian, and much more possibilities!
- Tile-based habitability. Introducing more granularity and flavour to planets and their management
- Introducing corporations and trade routes. Foster your independent intellestellar corporations or control your economy with the iron grip of the state
- New collectivist VS individuallist axis, with all the factions, policies and special perks that it entails
- New hivemind types, "devourer", "symbiotic", "parasitic", "cibernetic collective", "warp vampires" and "benevolent harmony" allows you to play wholly different types of unified consciousness
- Introducing nomadic factions, opening up never seen before gameplay possibilities and a brand new refugee dynamic
