Civilization 5 was controversial for ditching unit stacking, forcing players to space out their armies on a new hexagonal grid. Civilization 6 got heat for altering the art style, and added a new city district system to mixed reviews. Eight years later, Firaxis hasn't opted to play it safe for Civilization 7: Get ready for some long Reddit threads.
The most fundamental change, and the one I think will be the most controversial, is a revamp of the game structure. Instead of lots of eras—Ancient, Classical, Medieval, Renaissance, and so on—a game of Civ 7 is divided into just three ages: Antiquity, Exploration, and Modern. At the start of each age, you'll be prompted to pick a new civilization, with options that depend on your current civilization and the choices you've made so far. Mongolia might show up in your Exploration age options if you've developed powerful cavalry units, for instance.
