The colony system is interesting, but it doesn't quite do what you ask it to do, which is somewhat frustrating (at least in my case)..
For instance, in a game as the Dutch on a terra map, I had established a very important city in the middle of the new continent that acted as a landbridge between the two large oceans, while it was also surrounded by two spice plantations and two tobacco plantations.
After establishing four other cities on the northern part of the continent and getting hit by the maintenance penalty, I decided I wanted to release those four cities, while hanging on to that central city. So, I went to the domestic advisor screen, selected the four cities I wanted to release and clicked the release button..
Unfortunately, instead of just releasing those cities, I get the option to release / gift a multitude of cities, so I click the option for the ones I thought I had selected. George Washington then greets me very amicably and I move over to the new world, only to see to my horror that the central city had also been given away!!
(Aparently you can't specify exactly which cities you wish to release, which is a shame..)
I accepted the situation and moved on to colonize the lower half of the new world, with the inention to release those as another colony as well. This I did and when I chose to release them, instead of forming another Civ, those cities joined America, even though I had specified that I wanted them released and not gifted away!
So, suffice to say that I'm ok with the colony feature (despite the fact that I think overseas maintenance is ridiculously high at times), but I think from now on I might decide to stay away from Terra maps and the likes..
