Warpiglet-7
Lord of the depths
I would buy that.I personally think the appeal of Greyhawk lies in its vagaries as opposed to fully fleshed out like the realms. It was designed that way for a reason: here’s a sketched out world, make it your own.
Lean into that and it will serve a purpose and be distinct from the other current 5e settings. My envisioned 5e hardback would be heavily influenced by the style of Judge’s Guild Wilderlands of high fantasy.
chapter 1) Greyhawk flavour and themes : small kingdoms vie and clash, small points of light against the wilderness. A land of opportunity if you’ve the stomach and a quick enough blade.
include a page description of each era, highlighting that it is down to the Dm to decide whether they want to base it in original/wars/from the ashes or their own timeline.
chapter 2) fitting your character into Greyhawk
chapter 3) city of Greyhawk Gazetter.
chapter 4) factions and kingdoms of Greyhawk. (Keep it light and sketchy, only a page for each entry, just enough to give a flavour of each one)
chapter 5) The Flanaess. An updated Darlene map, with the 30 mile hexes. Included are key sites where locations are and where classic modules took place. Give a one paragraph key to each hex entry with reference number that gives a flavour of what’s there.
Chapter 6) Making Oerth yours. Explain the concept of hex crawls, talk about breaking each 30 mile hex down into smaller 5 mile chunks. (As an aside, I’d prefer 24/6 mile scale for ease but alas there’s precedence). Talk about how you can populate each hex with whatever you want. Put tables in to generate location/monster/event encounters for inspiration. Hammer home the idea is the sense of adventure, claiming the wilderness, diving into caves, tombs, strange towers for loot and glory.
chapter 7) conquering Oerth. This discusses taming the wilderness, creating your stronghold and your own fiefdom, and the struggles that may occur.
To my mind, this would highlight what is special about Greyhawk and make it a distinct and useful product within the 5e library.
Perhaps you could have a book that explains how to make a campaign and it just so happens to be filled with Greyhawk as examples you could use and run with—or—-just take it as a campaign design book.
Homebrew fans could use it as a generic reference and Greyhawk fans could use it for Greyhawk.
market it as a campaign design sourcebook to expand the market but also have it function as a Greyhawk setting as well.
totally possible and it would be a must buy for new DMs...the least likely to be into Greyhawk.