That there's more regions that haven't been revealed yet.
So really all we know are
Lucis Region (correct me if I'm wrong)
- Leide
- Duscae (Tabata said the whole thing including the disc and lestallum was 10% of the whole world map)
- Cleigne
Areas outside this region
Altissia
Snowy Area (west of the Volcano thingy)
Areas revealed we know exist but don't know where in map
-Tenebrae
-Nifilheim
-The greek/Santorini looking town that was revelaed in the tech demo/concept art
- The U shaped mountain past the sea shown in a lot of the demos when they drive to Galdin Quay
Also regarding the driving. If you look at this--
You'll see the
Marlboro area revealed to be on the continent west of the volcano. From that point to where the yellow line starts (presuming it's the train line) there aren't any indicated roads. This leads me to believe that the roads on the map only unlock either once you're in the region or you talk to a local and they unlock it for you (this was the case in the demos where Cidney unlocks the road map for Leide, Duscae and Cleide).