FoV was originally going to include a Broken Valley type area, but it was dropped due to lack of resources. Like you, Larian thought the game overall needed more of a human hub of activity, so that is what they focused on.
I was hoping Rivertown Gorge would be more than just a flying fortress, as well (though other than that didn't have a problem with the number or size of human settlements). I even tried entering the gorge on foot, rather than flying, to see if you could continue and get anywhere that way (and quickly had to transform before I fell far enough to die).
