Galactic Civilizations 2:Dread Lords is a great Game.If the following concepts are included in the next expansion then it would become a near perfect game...In my humble opinion.
-researching and constructing Ringworlds and Sphereworlds.(see the novel: "Ringworld", by Larry Niven) A Ringworld is an artifact constructed using a systems planets and asteroids to form a ring around the sun. The inner surface is used like a planet. "Shadow Squares" provide day and night cycles and solar power. A Shereworld, or "Dyson Shere", is the final costruction phase of a Ringworld. It is the ultimate engineering project of a civilization. A total sphere around a sun. The inner surface is used like a planet. An artifact to be feared and revered for its potential.
-researching and using terraforming. Planet atmosphere/environment to match different races (terraforming would alter a planet to a specific type and improve planet class).
-researching the ability to destoy planets and use the resulting asteroid belt to contruct a new planet again...and again...(This would require technology close to being able to construct a Ringworld.)
-researching the ability to destroy a star ,and thus its planets,and use the resulting gas and debris to construct a new solar system with a Ringword again...and again....(This would require technology close to the level of constructing a Sphereworld.)
-more civilizations per game; larger maps/galaxies; more races that are less humanoid; higher maximum number of planets per solar sytem: ten is a decent number.
-endless research: each "breakthrough" would lead to pluses to various categories such as military, diplomacy, happiness, industry, etc.Science Victory could be reaching a chosen amount above top rival(such as 3,5,or 10 times more advanced).
-multiple paths of simultaneous research possibbly using funding sliders.
-better proportions: solar systems "tucked" into one "square/space".You could then enlarge the "System View" where there are system "squares" for exploration, travel, ...and battle.
-expansion into multiple galaxies: via "regular " drives wich would take... a long time; and later something quicker like a gate or special warp/teleport.
-the in game,each battle,option of player control over battles...space and ground(though the ground part might need some redesigning).
-orbital bombardment of planets using any/all ships and weapons:beams,missiles,cannons,etc.There would be varrying degrees of dammage to the planets infrustructure,population,and morale based on the total ships attack value.
-planetary defenses such as missle bases, beam bases, fighter bases, orbital platforms, and planetary shields.
--Scitech