Well, now that the site is back up (YAY!) I finally got a chance to get a glimpse at the article.
Coupla things...
1) Hags: I'm with [MENTION=52734]Stormonu[/MENTION] in that I kinda see it, kinda don't. But then, it occurs to me, that there is no reason they couldn't be treated as both. A la gnomes are viewed in many worlds/games...just make it the default lore for the MM. There are "fey hags" that exist on/are from the Land of Faerie...and then there are the "mortal" ones that have come over to the Prime Plane (somehow or the other) and this is where they live now, often allying themselves with/controlling giantkind, unable or unwilling to return to their plane of origin ("exiled" or "banned" by the archfey for some gross transgression, etc...). Like the way that gnomes are mused to be from the Faerie world but now exist in the Prime..or, as in my own world of Orea, Satyrs are part of the prime as well while other, more "faye", satyrs [a.k.a. "fauns"] exist in the faerie world.
2) I thought the bit about "why they'd be in the MM" was...while making sense, a bit of a "miss". Unless they have jettisoned the whole "3 pillars" design philosophy, at least one of the reasons, if not the primary reason, would not be about "defining the world", but giving the PCs creatures to INTERACT with or be the source of something to EXPLORE, as well or necessary as creatures to COMBAT. But there was no mention about that perspective. I found it...odd...and a bit disconcerting that didn't seem to be part of his reasoning.