The game ranks as one of my all-time favorites for two reasons. First, the world isn't completely static. While the scenario you start with does set which cities do and do not exist, those cities may well change over the course of the game without your interference, making each game even set within the same era different.
On the other hand, if you want to get involved in war & politics, you have the ability to alter the map on a grand scale. The ability to overrun cities and change their allegiance, not to mention preferentially attack the shipping of a particular country will greatly influence the course of events. This kind of personal influence on history is rare, and rather appropriate for a game set in an area of early colonization, where individuals and sometimes serendipitous actions did often have an outsized influence on the success or even survival of settlements.