Pfeffersack
Deity
Amenities. Not broken in a direct sense, but they suffer for my taste from the same issue as Gold. It is too easy to fulfil your needs here, which devalues nice features like Luxuries or Entertainment districts. In previous parts of the civ series (especially Civ 5), luxuries or entertainment buildings were a huge deal; you could just never had enough and constantly struggled for more. In Civ6 I find myself viewing luxuries mainly as trade objects which go to the AI to fill my coffers with Gold. And I almost never feel pressured to invest in Entertainment districts, when they become available - usually I puzzle in a couple in the late game, when the Waterparks are available, too. It is a fun minigame to place them to reach as many cities as possible with the Tier 2 and 3 buildings...but it is by no means really necessary to make that effort and "local" ones to get the base amenity from the district itself and the one from the T1 building are almost never worth (pre-GS, I considered at least "local waterparks" to make better of use water tiles, but after all the improvement to them even that has lost its appeal for me)
A possible fix could be changing the formula of needed amenities for population a bit: Currently, you need one amenity for a city, when it reaches a population of three. And then one more for each two pop more. The amenity system would get a lot of teeth, if a city would eat up one amenity in the moment it is founded and then one more for each two pop more. Would be also a nice counter to mindless city spamming.
A possible fix could be changing the formula of needed amenities for population a bit: Currently, you need one amenity for a city, when it reaches a population of three. And then one more for each two pop more. The amenity system would get a lot of teeth, if a city would eat up one amenity in the moment it is founded and then one more for each two pop more. Would be also a nice counter to mindless city spamming.