Yeah, it's cool how if they survive long enough they can turn into a city-state.
'bout f'n time! I've been advocating this for a while now.
I'd also love to see some city-state diplomacy result in a new 'civ' joining the game in the middle by having a few of them team up, or one of them conquers a pair of barbarian camps and another city state and suddenly has a population base to become their own civ.