The design principles come from Josh's one page adventures. Josh is not a fan of the standard modules that most GM's are familiar with. Highly detailed maps and text boxes aren't really his bag and they kick his anxiety into overdrive. That was the inspiration for the Story Arc format.
I like to think of them like the annual comic book events that we all love and hate.
Josh already has one he's working on, Invasion!
Invasion will see Martian forces invading the city. The pdf will include stats for the martians and their advanced technology, detail various action zones the players can interact with, and even include what happens in the aftermath. Much like Spider-Man: Homecoming, we'll take a look at the tech that gets left behind after an invasion and how it changes things. Also, for those of you that didn't know, this Story Arc was hinted at in our Free Comic Book Day offering: Crisis on Free Comic Book Day!.
I've wanted to do a vampire-centric event and inspiration has hit me today.
If you need some vampire goodness to tide you over until it's release, check out Drugula and the Silver Screen.