After running in a, at this point, well established home brew world for well over 5 years in Pathfinder 1E, I switched over to 2E and began crafting a new world to indulge in my love of grimdark fantasy at the request of a player. Said player then had life happen, and left the game, which brought a chuckle.
That being said, I after years of reluctance to switch systems, I am enjoying running in 2E. Combine that with switching from running on Roll20 to FoundryVTT, my experience as a GM has skyrocketed.
The concept for the new world is, what happened when the heros failed? The world had a cataclysmic magic disaster, resulting in most people hiding underground for over a thousand years. In the last few centuries, the reclamation of the surface has begun. I use modified Manga Wellspring rules outside of established cities/towns, utilizing the concept of flipping a coin in magic fallout areas from Terry Pratchett's Discworld.
My players have expressed that they are enjoying things so far, and I can't wait to see what they do when they get out of their current situation (first real job, which has led them to a ruin) and things really kick into gear. :D
Did you boop the snoot of Mittens the Murder Kitten?