Natural growth of the city

Cities grow more naturally. Your actions will affect growth directly and may result in asymmetric growth of cities, for example, if you provide industrial cargo, the city's industry will grow, if you provide commercial cargo, the city will receive more commercial space. Cities will be smaller at first, but could grow much larger.

Details:

By default, the game randomly determines the starting size for each city in approximately the range of 80 to 220. This number doesn't change much over time (there are small random increases that can increase the original size to around 330 in 2000), meaning that some cities will forever remain smaller than others due to a "bad shot" at the start of the game. Your actions can only affect city size by using a percentage modifier based on supply ratings, availability, and environmental factors. This percentage modifier is applied evenly to residential, commercial and industrial dimensions, which means that these values will always be approximately equal.

This fashion changes the city's growth to give you more control. Initially, each city still gets a random size, but with less variation. In addition, residential, commercial, and industrial dimensions are determined independently (the city details window displays only one "starting size", but each of the three boroughs actually has its own value). These "initial dimensions" grow over time depending on your actions. Industrial cargoes produce more industrial buildings, and vice versa for commercial cargoes. All sizes also depend on the availability of the city. The size of dwellings is more dependent on accessibility, while commercial and industrial sizes are more dependent on supply. The original percentage modifier still exists (because it cannot be removed), which means that increasing availability, supply, or environmental factors still affect all sizes.

When you start a new game (or turn on the mod for an existing game), it will take some time for cities to adjust to their new size (for a new game it will take about 1 year, for existing games longer depending on your progress). Also note that the game seems to have a built-in limit on how big cities can grow, so at some point you can see how the city stops growing regardless of the "target size".

In the last image above, you can see the numbers in detail. Note that the "scaling factors" are only used for the base power, that is, their impact decreases over time as you begin to connect the city and supply it with cargo.