Hey there.
Speaking as the chap who has been responsible for some of the shake-ups to the Dead Lands map and southern continent over the past year, as well as the person who made that new Dead Lands and southern continent map (Development Discussion for Dead Lands - #20 by neujack), the reason why I’ve done this was to fill the gaping hole in the map left by the Cartographer’s Guild due to simply not having the information.
The only part of this map that is set right now is the red box, which is in the upcoming Dead Lands book. The rest I included in an effort to contain the blackglass. And all those other areas are open to development and detailing by whomever feels up to the task. 
I wanted to give you all something to play with surrounding the lands, and there are even some sections of the obsidian plain which haven’t been detailed yet. So we’re open to ideas…