Level Up Balance Mod
This is my attempt at rebalancing the leveling up of the buildings some.
It recalculates values for all of the buildings and tries to create a smoother and more logical progression. Offices and factories won’t upgrade unless there are enough workers already working at the building with a high enough education to adequately staff the building when it levels up. They also have simpler requirements for service coverage, so no more needing schools, graveyards, and parks for your industry. Offices are slightly affected by these things due to them now prefering higher land value areas. Also, having a higher average education level of your city will help the industry and offices to level up.
Residences have been rebalanced as well and require decent service coverage to level up, as well as high education. Land value requirements for level 5 buildings are that almost everything is completely taken care of service-wise. Mass transit helps, while a bit of pollution or excessive noise pollution can prevent the level up. Commercial buildings also take quite a lot of land value to hit level 3 now.
In the unmodded game, it is possible to level up buildings by doing silly things like building multiple large fire stations, police stations, and hospitals in an area to raise service levels and land values. My mod has a much lower cap on services, so that as long as the road is solid green, you should be fine, and building more services won’t help buildings level up (because they are already 100% covered).