Despite having a brief appearance at the E3 PC Gaming Show, Civilization 6 did have some significant reveals, which are now up on video game news media streams. Here are the confirmed changes in Civilization 6 which set it apart from its previous entries.
Civics Card System
As seen in the E3 reveals, the Civics system works like equippable bonuses that grant certain boosts to your Civilization. It was previously confirmed that Civics will work like a tech tree, so players might have to research Civics technologies that may grant Civic Cards that they could mix and match later in the game.
Wonder Building Requirements
As discussed in TPangolin?s Civilization Reddit thread, some wonders will have to be built near some improved resources or a city district. For example, the Stonehenge needs to be built on a flat land near a Stone tile, and the Great Library can only be built near the Campus city district with a Library. Wonder building is more particular in Civilization 6, making Wonder building races a little more difficult without a variety of convenient tiles in your territory. This is entirely different from the previous Civilization 5 where there are no limits for having Wonders in a single city and Wonder building races are strongly decided by superior Production tile yields and Great Engineers, if available.
Capital Razing and No Puppet Cities
In Civilization 5, taking another Civilization?s city gives you three choices: take it as one of your cities, set up a puppet government to avoid its occupied city?s disadvantages, or raze it to clear its territory and remove the city in the game. Razing is not possible in a conquered capital, however, this system is not confirmed when conquering City States.
Most players either choose puppet or raze to keep their own Civilization?s Global Happiness healthy. Global Happiness is turned into separate Happiness per city in Civilization 6, so puppeting cities may not make sense unless occupied cities have a different set of negative yields to a player.
Additionally, in Civilization 6, players can only take or raze defeated cities. Players can also raze a capital, which makes it possible to erase every trace of another Civilization if it?s thoroughly defeated. It?s unknown yet if players are forced to annex conquered cities or keep it as a puppet city for extra territory and tile yields for their Civilization.