As I understand it it is the Reikland that is what will be detailed of the Warhammer world in the core set?
Not a bad desicion to actually have a focus on a region then almost a whole continent. And it makes sense in a designer perspective. Reikland is the hotspot of activity in the Empire, maybe not on the borders of war, but still where a huge number of the empire humans live and many races visit (Marienburg is another place like this but independent).
One thing I do hope is that the setting books that very much likely will come will be meaty. 2nd ed Empire book was to thin and you could learn more about the empire by reading a few novels or searching on the net. But I also hope that there will be an Empire book, and not a book for each region - Rather a fat more expensive book, then several smal, not so expensive books but still quite expensive - as much of the FFG books are.
Also hope there will be a focus on setting books compared to adventure boks and equipment books.