(these may or may not be used)
-Better Map Editor
-Import Civ2 scenarios and maps
-Hotseat mode
-Improved missile movement
-Different kinds of cities (colonies, permanent settlement, etc.)
-Border/Frontier control
-Negotiations over land rights
-Must supply people with drinking water as well as food
-Major and Minor Civs
-Bigger maps
-More civs allowed in game
-Advanced unit grouping/attacking
-unconditional surrenders
-civil wars
-Assassinations
-Manipulate the media (?)
-Smarter senate
-Chemical and biological weapons
-Random disasters/events
-More religion things incorporated
-scandals
-supplies
-colonization
I doubt you'll see all of these features because it would just make the game too complex.