So i just concluded running Wrath.... it was fun (despite my party being waayyyy to big). We even ran through the future years for the character and the world for a bit. My question is... what is the official post mortem for that campaign? has anyone written that and if so where. Just curious. I assume they took the "Hero's quickly vanish from the world" option because otherwise the rebellion in Cheliax would become an afterthought for the 20 level 10 mythic tear worshiper of good god x. But what happens to Medev....what about the left over Demons not in the campaign, at least 2 of which were written as mythic. Just curious if anything has been said or published on aftermath...officially.
I cannot recommend the Worldwound Campaign Setting enough. There are plenty of high-level demons in command of the various sections of the Worldwound as well as plot hooks. You need to consider that the end of the AP doesn't completely remove the demons from the world, and the veil between planes has always been rather thin in Sarkoris. If any powerful demons or cultists are left alive by the end of the campaign they could very well open a new portal and start the whole thing back from square 1.
One step to restoring Sarkoris would be to retake the Stonewilds to the north - it was once home to the oldest-known holy sites and settlements of the Green Faith, whose druids were so powerful and incorruptible that the demons considered them a greater threat than the Crusades. After being pushed to the brink some of the faith's greatest druids performed a ritual which turned the very trees themselves to stone and pushed back the demons at the cost of their purity - by taking the land's corruption into themselves they became undead monstrosities called Siabrae capable of using druidic magic despite being outside the natural order. These particular siabrae are powerful enough to rival the Storm King himself and guard their land against all intruders, especially other druids.
Our campaign just started book 6, so quickly getting to the end ourselves. I would say that the PC are much too powerful to be left "in setting" just as king or hermits or something. A couple of options:
1) Taken up to the planes as divine servants: this already happened to our paladin (who had to quit for family reasons). If you are a semi-divine being you can be remote enough that he won't immediately be seen as option #1 for any issues a good kingdom is having issues with.
2) Mythic Power is used up: PC use their Mythic power to fully kill Deskari or to finally close the WW for good. Mythic power may have had a divine source and thus your quest complete, the divine power is then withdrawn. Instead of wielding phenomenal cosmic power, you are "merely" ultra-wealthy 20th level characters. Good enough to rule a region or country, but not sufficient to singlehandedly take on any other threat to the material plane.
3) Scatter to the ends of the known universe: PCs choose to go off their separate ways to fight great evil wherever they can. One could go to lead the charge against Treerazor and the Tanglebriar (the elves own mini-WW). Another can go traveling the stars learning about new things, never to return to Golarion. Similar to #1, one may go off to other planes of existence to learn ancient knowledge/kill bad guys.
4) They ascend to the planes as Demigods: pretty self explanatory
With the exception of #2, these all assume PC are out of setting. This I feel is a necessity for you to eliminate the issues of having so many powerful being running around in setting. There are no more evil kings or great wyrms or demiliches, because the PCs, after killing a demigod, thoroughly cleaned out the rest of the trash with their god-like powers and infinite resources.
I'm not aware of anything official. That said, WotR more than any other AP would be highly personal. When you've got a handful of people who escalate to demigod power levels, "what happens next" is: "whatever they want."
In the case of my PC (human psion), he's made Drezen his home and runs the place, while starting a family with a certain female NPC, after having arranged a certain female NPC couple to be crowned Queens of Redeemed Sarkoris.
Meanwhile, his faery dragon Leadership cohort has kept her special job working for Iomedae, and is very likely involved in the chaos that's beset Chelliax recently... because faery dragon.
Point is... what happens next is up to the players and DM.