Any city I can get my hands on, gets walls; yeah, Neuschwanstein IS part of 'the plan', but ya never know when an AI alliance will bite you on the ass .
Ogilarchy, with its Garrison (+50% defense on ranged), plus Military Caste (+on Happy, Culture), boost your city's chances of survival, and help 'fund' Liberty's expansion prospects .
I find Raging Barbarians to be a tool to use, and joyfully abuse, for setting up serious warmonger steamrollering !
I want all my cities to achieve 'stand alone' status, and with a few units per city, you can go past the 4-6 city framework of Tradition and Liberty; securing quite a swath for a stable, profitable Realm, ready to expand as opportunity presents itself .
Huge maps offer huge results .