The games you mention are military games that focus on tactical battles.That will most likely have lame duck A.I like the rest(RTW,etc) and very little depth in other parts of the game.Aka diplomacy,economy,planets,tech,culture.The only 4X game that has some of my interest (apart from GC2) is SpaceEmpires5.
Galciv is a true 4X game that will have equal focus in all parts of the game(like civ4)and will still be played in 5 years, or untill GC3.