Realize that your post was a couple of years ago, but Sembia, Dragon Reach, and southern Lake of Dragons were off limits at the time for development. They were intended to be zones for the public. Raven's Bluff/Living City/the Vast was for the RPGA campaigns. It was kind of a big deal for some when the Erevis Cale books started coming out because suddenly they were touching the untouched.
Other people got to this, but Dalelands was Ed's area and then Cormyr, Moonsea, Sword Coast were parceled out for modules, video games, and novels. Again, in light of the stuff that was barely developed with a couple of sentences, you were supposed to be filling out the other things so that the novels/games could do their thing without putting you into a continuity crisis... except for the obvious stuff when changing editions.