IMO, the Industries DLC makes it strongly about traffic again, with the huge amount of industrial traffic it generates. Then, once you run out of space in the relatively small 9-tile city area, there's not much city painting left to do. It's been a long time since my main city was about city painting; it's all about traffic again.
Honestly, I rarely play the game with 9 tiles. It's much more fun to unlock the entire map and work with a bunch of smaller satellite towns connected to the main one, local rail transport, perhaps a few villages with farms etc...
