This is, from what I can tell, an example of that extra broadness I was saying may or may not be worth the extra cost, of the NWCS vs. something like Hammerfast, depending on your mileage and how it varies. If you already have the FRCS and/or access to old maps... or are willing to put in the extra work to create your own maps, including that breadth concerning Thay is great. Otherwise it's just wasted words at a higher price.
Or you know, could make a player/DM want to purchase the FRCG to expand out into the rest of Toril or the Shadowfell book or the planes book. You have to have hooks in it for other products.
Besides: broadness isn't really avoidable when you have one area on an entire planet which itself that's already been highly detailed. Something from the "outside" is bound to slip in.