here’s a fairly recent comment from one of the live streams:
Will there be colonization aspects to the game, where form your main city you have satellite settlements?
“That sounds like a great feature for an expansion. We want to make
sure we nail one city management, that’s not to say you can have only
one city. If you chose to send some guys off and make two cities we’re
not going to stop you, but that’s not what we are going to optimize
for.”