I have used the search option, and found nothing about this idea.
I'm thinking of making the worldmap a place that shows a bit more detail about the world surrounding you. Let me explain.
My idea is to put some more information besides the standard wm grid info: coords and zone. This info would be:
- the type of terrain the zone lies on (mountains, city, plateau, dunes, plains, desert, sea shore)
- travelling speed penalties you will suffer when travelling on that terrain (different values for different circumstances: character's outdoorsman skill, pathfinder perk, the type of car you drive)
[Example]

Mountains: -50%
City: -40%
Dunes: -30%
Desert: -15%
Plateau: -10%
Seashore: -10%
Plains: no penalty
[/Example]
This would help to reach your destination by choosing your way more wisely.