So, I need to go get this book, I've enjoyed the PDFs the gentleman who compiled it made before it was picked up by WotC.
I'm a long time Realmser - fell in love with the setting with the first Grey Box, and I did really enjoy a number of the sandbox supplements that they put out through 2E - things that gave a sourcebook or boxed set of detail on an area, and several plot hooks and nice "possible" adventures.
But originally, it didn't come off as demanding (not that it really can, since in the end, you as the DM have final veto power on adding anything to your world) that you follow it's many possibilities. But it did add more and more links to their progression of the timeline making it more work for a DM to add things from new supplements.
While occasionally irksome, I took what I liked and needed, and ignored the rest.
When the FRCS 3e came out, I really enjoyed the layout, and the encapsulated detail - but I found myself disliking a lot of the new situations that the timeline advanced, especially since I've never tried to "kept pace" with the timeline. I also found myself at odds with how many of the core villains and NPC patrons goals seemed to have shifted from their PoV/purpose without adequate reasons (or perhaps adequate if you'd read the novels, I don't know, it's been a long time since I've had the time to read a novel, FR or otherwise), or had weird catastrophes happen to them which didn't fundamentally stop them and then the spell/item/organization that had turned on them went back to supporting them on some level (I'm looking at you, Manshoon Clone Wars).
As I followed the 3E progression of the Realms, I basically saw them, with each supplement, dragging down and destroying the structure/bastions/safe places that are the Realms' hallmarks, while saying that the PCs were the stars, while not providing any real good resources, in my opinion, for the PCs to be heroic in defending or strengthening those areas of respite, or just doing heroic things on any scale from small/local to world/plane spanning - barring adding a massive plot which was a campaign driver with such broad ramifications that it couldn't easily be added to an exisitng campaign without derailing it (Dragonsfall War, I'm looking at you).
But it's always been a high fantasy setting, where there's weird stuff in the wings.
I can honestly say, I understand the marketing reasoning for wanting to make a "fresh start" for new players, or removing NPCs/tropes which some people believe are too abusable in the game to retrieve players who gave up on the Realms farther back, while retaining a branding that is known (good or bad) throughout the gaming community, because, well, it's known throughout the gaming community. Brand recognition is what it's all about when it comes to marketing, after all.
And I haven't liked the direction it's been heading since about mid 2E, but there's usually been enough tidbits to glean from the sourcebooks to add stuff that I wanted that had easy ties to existing material.
But this is less a horrible surprise, and more a last nail in the coffin for me. If I wanted post-apocalyptic fantasy, or grim and gritty low fantasy, or what have you, I would've run a different setting, likely with a different system. What little spoilers and speculation are out, do seem to suggest a setting which has had it's overall genre and several of it's tropes changed, to the point that it's not the setting-type that I want to run/play in.
I do hope that it does what they hope, and brings new players to the table and the community, I just can't see myself buying the material. I have all the material I need for the Realms as I see them, and as they've progressed in my 13 year campaign along their own, now quite variant, timeline.
So, I guess this New Realms just isn't for me, and that's kinda fine by me. If it works for the hobby, good for them; I'll be playing in my personal home variant, probably in an alternate system to 3.5, which even I think made some things in the Realms too wacky for different mechanical reasons.
C'est la vie