The default setting for a DF game is a city, but one you start getting into the 10-15 refresh range, a city can start to seem pretty small.
If you have a small group, this might not be a problem, but a single city can feel pretty crowded with 5+ characters, the antagonists, the non hostile people, etc.
So, how can you use the same aspect based setting generation for something larger?
The simplest way is to just make the setting 'regional' instead of a single city, so you could expand your setting to something like 'Along the Mississippi' or "the aegean" instead of a single city. Locations might be switched from singular locations to cities or regions with particular character, for example 'The Las Vegas strip" or "out in the desert" become locations.
Another way to redefine aspects it to make the aspects related to the part of the world the characters 'see'. For example, for a wardens game, no matter where you go, there's some sort of horrible magical crime. If there wasn't, you wouldn't be there.