Saying role-playing games copy Twilight is like saying AD&D copied the Dungeons and Dragons cartoon.
Dropped the stones, and made Ioun a "default" goddess of magic. Can't say as I'm happy with the decision, myself.
EDIT: Correction: I checked the compendium, and they have been re-introducing Ioun Stones a bit at the time.
What would you say is the meta-plot focus of FR? Is it significantly different from say the GH metaplot of the greyhawk wars introduced in 2e?
With the 3e FRCS I felt it was similar to the LGG in providing a short entry on a ton of countries and gods so you could pick a place and go run with it.
With GH, there hasn´t been much canonization going on, as far as I can see.
It depends on the books you bought. If you´ve bought the FRCS and nothing else, I´d say you have more or less the same.
But most of the later sourcebooks (and Dragon mag articles) also included more of the book plots into the canon, adding their more or less substantional meta-plot to the whole. Return of the shades and the Lloth-thingie as an prime example.
With GH, there hasn´t been much canonization going on, as far as I can see.
What about Age of Worms?
It's not been easy for GH because its canon material was scattered like shot all over the D&D map. In 3x GH was publicly declared the default world, plus Dragon and Dungeon Mags had a little blurb in the corner of every issue that said 100% Official Content. So, technically everything WotC and Paizo put out that related to GH was all canon at that point yeah? The rub with GH fans I'd guess is besides the LGG, none of them had a GH banner across the top like we're used to since the old TSR days, also GH fans have been burnt by b.s. canon before. Then throw in the RPGA's literal thousands of published adventures and even the most stalwart GH advocate working for WotC would have a hard time tracking what's canon anymore.
So the fact recent GH hasn't been burdened with this set-in-stone canonization is probably an advantage over FR at this point.
What about Age of Worms?
Hate to correct ya Hussar as I agree with the spirit of the post. I just don't want people to be confused. Age of Worms was the paizohawk AP that was set FIRMLY in the central Flanaess, using Greyhawk City and its environs for half the quest. The follow up, Savage Tide was set far far away and the preceeding AP, Shackled City was retrofitted into the Flanaess a while after it was concluded.