Why not a menu of pre defined default terrains you then tweek. If you look at our map rotation from a 50,000ft perspective, you can see that in them.
You either want dry land mass outlines with water and no high elevations until you pull those up from the base elevation and change the land mass shapes. Or the same but, with predefined mountain ranges that you tweek the lesser features and reorienting the geographic run and elevations of the mountain ranges. Kind of like crabby in a sand box hopping up and down on your sand castles.