Here I have some thoughts about game improvements, that will not only add more realism, but also will make game features more balanced and fair. Sorry for my bad English. 1. Knowledge spread - Scientific improvement. Technology already known by other civilizations should be reseached faster. For example, in a game with N civs, technology known by M civilizations will be researched (M*100)/N % faster. RL background: In real history, only isolated civilizations remained technologically backward. In fact, every technology is easier to discover, when it was already discovered by someone else. In-game reason: This will make technologically backward players less helpless. Possibly, this will make beelines less effective. 2. More techs - Scientific improvement. I know about Occam's razor, but currently there are too few techs and this makes research agreements and lighbulbing too effective. This improvement also has synergy with improvement #3 (see below). Later era should have more techs than the earlier one. RL background: There are lots of important techs, that were not mentioned in Civ 5 - diesel engine, continuum mehanics, lather, gas turbine etc. In-game reason: As already mentioned - too overpowered RAs and bulbs. 3. Unit modernization - Military improvement. While some techs make terrain improvements better, some techs should make units better by giving them upgrades. For example: Machineguns - Infantry gains +50% defense against gunpowder/melee/mounted units. Grenadiers - Riflemen gain +15% in combat against gunpowder/melee units. Bayonet - Gunpowder units gain +15% defense against cavalry Satellite guidance - Ranged and air units gain +15% against land units. Smokeless powder - Ranged attacks deal -25% damage to gunpowder units. etc. RL background: Actually, military technologies evolved more smoothly than they evolve in game. Also, this feature will allow to represent some events like WWI "trench war". In-game reason: This feature should make something like "slingshot to steel" less effective, due to upgraded classical-era units. This also will allow to give mech infantry, for example, 40 initially (with modernization to 50 with later techs), making tanks more valuable. 4. War reason - diplomacy improvement When DoWing other player, player should choose a reason for war or declare that there is "No reason". "No reason" gives relationship penalty with all city-states and/or "Permanent war" with one of city-states. Some of the reasons should have a "goal" - You should achieve the goal or end war without capturing enemy cities/returning them. Otherwise you will have a relationship penalty with all city-states and/or "Permanent war" with one of city-states Possible reasons: Liberate a city-state. Recover own lands - applicable, if someone captured your initial cities. Protect the city-state - city state should survive and sign the peace treaty with the enemy. Save the world from the warmonger - declare a war on someone, who is in a war for no reason. Sacred war - one of piety policies should allow to declare a war once with this reason. etc. RL background: I think it's obviuos. Almost every war in civilized world had it own excuse given to the society. In-game purpose: Giving penalties to warmongers, making diplomatic victory really diplomatic.