Hiya.
I'm going to add my 2 coppers in here...
I think there is a bit of a "generation gap" thing going on here. Back when I started DM'ing (1980), adventure modules were fairly skeletal as far as "story/plot/NPC-interaction" went. Why? Simply put, story/plot was up to the players actions and, basically, the DM's job. The person writing the module doesn't know what your campaign world is like, nor does he know what kind of players you have. So, all the stuff that would actually take *time* was in an adventure...maps, encounter tables, a new monster or two, perhaps a new spell or magic item. *That* is the stuff that sucks up a DM's time. Drawing out 3 full-page maps and "stocking" them (as it was called in the day) took a hell of a lot of time. Scribbling down some notes about how Evil-Bad-Guy plans on subjugating the small town and setting it up as his own base of operations is *not* where time is spent. If I had to estimate how much time I put into story/plots/sub-plots vs. drawing maps and "stocking" them....I'd say it's around 1:4 (that is, for every 10 minutes writing down story/plot ideas, I do about 40 minutes of drawing/stocking).
As an example, one campaign I recently run, I used "Dyson's Delve" (here:
https://rpgcharacters.wordpress.com/maps/dysons-delve/ ...I used the "Dyson's Delve Delux" PDF). The campaign was low-powered 1e set in my personal world of Eisla. There is a very loose story premiss...which I ignored and substituted my own. In my story, a young boy named Billem got upset with his father and ran away, finding a cave entrance to the top level. Billem was captured by some lizard-fish kinda guys who live in the very lower depths of the dungeon; they were planning to sacrifice him to awaken their "god" (a magically-enduced sleeping black dragon). During the course of the campaign, the PC's were almost captured by cultists, almost eaten alive by a hoard of giant rats, attacked by a group of bandits lead by an evil witch-woman who wanted the dungeon for herself, and got stuck in a time-trap. The time trap had two NPC women who were watching the 'camp' up in the cavern/entrance on dungeon level 1 take them for dead. The two women took all the camp stuff, including treasure, two horses and a mule, and head off to the closest settlement. Of course, the players all think the women "screwed them over", and are planing to hunt them down...just as soon as they rescue Billem (or recover his body). There is much more to Billem then anyone knows...and that will be revield when the time is right. At any rate, the point of this little aside is this: comming up with the base story and NPC motivations for this campaign (which lasted about 6 or 7 months...and is on pause right now...may start again this very day!

) was the easy part. That took all of 15 minutes. Now, if I had to draw out and 'stock' all 11 levels....I guarantee it'd take more than 15 frickin' minutes!
So...hearing stuff about Ghosts detailing "NPC motivations and story for a few pages"....that does NOT fill me with a sense of calm. In fact, much of what I read pretty much finalizes my initial prediction: WotC will create a decent 5e system, and it will then slowly tank due to crappy 'adventures' that can pretty much only be played one way, one time. If they give me a 5e "Keep on the Borderlands" in the same manner that Kenzer & Co. gave me a Hackmaster version of it...I'll eat my words and be changing my shorts. Unfortunately, I think we'd get something where Keep on the Borderlands consists of a small keep with 6 areas detailed, a map of caves A and I (all the other dungeons would have "caved in long ago" or something lame like that), and the other 20 pages would have story lines and NPC "information" and why they want the PC's to go to the Caves of Chaos.
^_^
Paul L. Ming