Open world games need the open world to work with how players explore and interact. Interesting sites should be visually distinct from each other and the environment, and frequent. They should not all be visible at once, to avoid players being overwhelmed with unclear choices. They should all be rewarding so players are confident they aren’t wasting their time visiting. There shouldn’t be important content hidden from visibility because then the game is teaching the player that looking at the world is futile. And the world should be navigable without the UI, i.e. the players are focused on the world and not the UI.