Found this interesting in one of their endless blogs. More tidbits are at https://goblinworks.com/blog/
Theme Park vs. Sandbox PvE
Pathfinder Online has a primary emphasis on sandbox style content. In brief, that means that your character's actions will have persistent effects on the game world, that you'll be interacting with many other players and their characters, and that you'll be able to self-direct a lot of the challenges you set for yourself, creating interesting stories using various objects and systems in the game as you see fit.
Many people think PvE content is necessarily "theme park" style content. In other words, your character won't have a lasting effect on the PvE content, and you'll be expected to play in a reactive mode, responding to scripted challenges created by the developers as opposed to the actions of other players. We do see a place for some content like that in Pathfinder Online; the idea of "dungeon modules" is deeply engrained in the tradition that Pathfinder embodies. But we also think there are interesting ways to develop sandbox PvE content too.
"Dungeon" is a catch-all term that refers to any enclosed space for adventuring. It need not be a constructed space; it could be a natural cavern or even a forest, jungle, or other terrain type. Typically, dungeons are designed so that they become progressively more challenging as they are explored, often culminating with a materially hard challenge at the end. A variety of obstacles must be overcome to reach the end content, such as monsters, traps, locks, illusions, hidden doors, puzzles, and complex interactive events involving the denizens of the area....
What we'd like to do with Pathfinder Online is combine an open world approach to design with this kind of theme park content. As you explore, you may discover a dungeon entrance. So long as you don't go inside, that entrance can be found by other explorers. Once a character enters the dungeon, though, that entrance becomes "locked" to that explorer; other characters won't be able to find that entrance. A character with access to an entrance can form a party and the party can enter the dungeon as a group.
If nobody finds the entrance, or none of the people who find it enter it, the entrance will be removed from the game world after a fairly short period of time, and it will respawn elsewhere. If the dungeon is entered, it will remain in the game world a longer period of time. If the final challenge is overcome, the dungeon will be removed after a short interval (giving you time to make several trips to and from the dungeon to haul out the loot within)....
Some dungeons are small areas that are randomly created by the game. There will always be a certain number of these in any given hex. That number will fluctuate based on conditions in the hex. As they are completed or abandoned, they'll be removed and respawned automatically. As you explore, you'll always have a chance to find something interesting.
Other dungeons are larger and more complex, and are generated as a result of the questing system. When a character receives a quest that involves a dungeon, that dungeon will be generated in the game world, but it will not be discoverable for anyone except the character with the matching quest. A party of characters, though, can share their quests so that more than one individual can search for the entrance. Generally speaking, the only characters who will find and adventure within these kinds of dungeons are those participating in a given quest. When the dungeon is abandoned or completed, it will automatically be removed by the game.
There's a third kind of dungeon, the largest and most challenging type. These are often designed to have several different entrances, each of which could be discovered by a different character, and shared by several parties. While exploring this kind of dungeon, you may very well encounter other characters! Fight, parlay, flee, or join forces—the results are up to you. Challenges in these dungeons may even require coordination between groups to complete—one party might have to fight through a room of undead to lower a magical barrier so that another party can access a different part of the dungeon...
Not all PvE experiences take place in dungeons. The Crusader Road area is home to many monsters, and they don't always live indoors.
When you're engaged in harvesting a resource, you'll attract wandering monsters. The longer you harvest, and the rarer the resource, the more challenging those wandering monsters will be. Every harvesting expedition thus becomes a PvE experience.
Some hexes will have encampments—areas where monstrous humanoids have taken control of a space. Encampments begin as fairly small, easy-to-destroy sites, but left unchecked, they'll grow, become better defended, and produce more and harder opponents. They'll eventually escalate, spreading new encampments around the hex, and those encampments will develop as well. If you don't take care of your kobold problem when its small and manageable, you could end up with a full-blown kobold infestation making life hard for the whole hex. Finding these encampments and eliminating them will be a constant source of engagement.
Occasionally, a really dangerous monster may appear, something that is so tough that many characters working together will be needed to kill it. Think about a dragon, elemental, or demonic outsider as examples. These creatures can rampage all across a hex, dealing death and destruction until a large enough band of heroes assembles to take it down.
The Design in Summary
As you find and explore theme park content you should have the sense that you're accomplishing something meaningful. And there should be enough of it that everyone who wants to can engage with it. The results of those encounters should lead towards integration with the rest of the game world and create interesting moments of interaction with other players. PvE shouldn't be an isolated pursuit of just a small cadre of specialized characters; it should be something that many characters interact with as they develop and pursue their objectives.