There was a dev post last week regarding switching a character's city-state, and they have confirmed that is indeed likely coming in patch 2.1 ^^
Quote:When starting the game and selecting a starting class, you will be assigned to the city-state where that class resides. However, we understand that some users wish to belong to a different city-state even though they started with a specific class. We are currently looking into a system that will allow you to change your city-state affiliation, and we are doing our best to have this ready for patch 2.1.