Hint: They aren't! But houses growing outside their walls made them look so massive compared to AoW4.
How to add that on AoW4 without ruining readability? Easy: Make houses grow around farms like mushrooms on a petri dish.
And the best part? You ALREADY have the house assets from each culture so it would be minimum work, maximum benefits. BAM! Easy massive cities. You can now be the Lord of Aesthetics. They could also grow around the city's province. It makes sense, doesn't it?
Let mines remain mines, but turn cities into province-large cities and farms into villages!