I’d be reluctant to mess with Adjacencies. They work so well already, and are so much fun to play with.
The key thing is that flat yields inherently devalue population and therefore discourage tall or fat cities. I think the game can tolerate flat yields for District adjacencies, because those yields at least are map dependent and still sort of related to population via District limits. But the flat yields from buildings, and the ability to multiple flat yields via policy cards, are where things get really hairy.
Overall, the game needs to generate more yields from pop (ideally pop working tiles or slots) rather than via flat yields. And, ideally, economies generally need to fluctuate more, so you can’t be so confident that you can just ignore / take for granted things like yields, happiness, amenities, maintenance and or (loyalty) (although, in fairness, loyalty is already a bit more dynamic overall).
Given that, my feeling is that a good rebalance that encourages fatter cities but keeps the existing Civ VI core design would be something along the following lines.
- Keep District Adjacencies, although maybe tone down Campus adjacencies and or find a way to restrict how many Campuses a Civ can have.
- Keep Natural Philosophy type Policy Cards, but maybe find a way to limit how easy it is to multiply adjacencies and or how many Cities these multiples apply to, so they don’t totally overwhelm population yields generally (maybe already less of a problem if you find another way to limit Campuses).
- Mostly get rid of flat yields for buildings. Instead, have buildings do things like buffing tiles, provide other effects, or maybe provide percentage bonuses (?). That should hopefully make Specialists more important for yields.
- Maybe buff Specialists, either directly or via policy cards.
- Rework Rationalism type cards. These cards really cause so many problems - pushing players to cookie-cutter +3 Pop 10 cities, and just making flat yields even more important vs population. There’s probably a million ways to make these cards better. One idea I’ve been thinking about is reworking the old Work Ethic Mechanic, so you maybe get +1% to yields per district adjacency and per pop - that would keep adjacencies relevant late game, but also make Pop more valuable because it both provides a source of +% and also any yields generated by the pop gets multiplied by the %.
- Maybe take a look at Neighbourhoods and Sewers for a balance pass. Maybe look at tech costs overall.
- More dynamic empire management. Personally, I don’t think increasing maintenance costs are a good idea, because it really does seem like Civ VI is balanced around having large Gold and Faith surpluses. Instead, maybe amenities could fluctuate more - currently it’s really only War Weariness, Bankruptcy and be World Congress which dynamically impact Amenities, and none of those matter very often. I’m sure other things could be introduced to make Amenities more dynamic, that would then make juggling wide / tall, pop and yields more challenging.
The key tweak needed around buildings and policy cards. I’m curious whether FXS might meaningfully tweak those in one of the next couple of updates. FXS have tweaked envoys and happiness, so I’m somewhat hopeful. Guess we’ll see.