The mark of a good open world is one where I want to actually engage with the world, almost at the exclusion of the "main content". Games with poor open worlds, such as Batman: Arkham Knight, Horizon, or the pre-Origins/Odyssey AC games, fail on this front, and sort of poison the well for how open world design is perceived. A game where I never want to quick travel, or use the Strand System because I would much rather actually engage with the world you have created because of how well it is designed, is an actual well designed open world. There are very few such open worlds, honestly. But I think Death Stranding has joined that league.