got in on the action mainly to promote their Curse of Strahd storyline. There was not much if any Greyhawk asked or mentioned in this thread. But one post involving "clues" seems to have captured people's attentions:
"Curse of Strahd represents an acknowledge of D&D's greater multiverse. We will continue to tell stories in FR, but CoS is a shot off the bow of everyone who professed that Wizards would never go back to its other classic settings. We foreshadowed the coming of CoS in the core rulebooks. The core rulebooks contain lots of clues about the stories we intend to tell going forward."
Clues based on references in the core books? Easy enough. Let's get the obvious out of the way:
The cover of the DMG as described inside, is the lich Acererak raising an army of undead to unleash against the world. There we go, big villain, story framework, artwork, higher probability of happening. My dismay is that this isn't Vecna. Acererak is just a dusty skull around the time of Tomb of Horrors so using Ace' kind of messes with my timeline sensibilities.
The cover of the PHB is Snurre, the main fire giant villain of Against the Giants. The probability of a giant storyline is ridiculously high anyhow, but would Snurre and a bunch of giants really be the best gateway to Greyhawk? I dunno. I'd rather Acererak was turned loose in my opinion. There's got to be more out there.
I will look more into these implied core book clues in the coming weeks. Keep digging friends!