It's a problem with game design and advertisement. In game design you need walls of some kind because your game can't be infinitely large. So either you put awkward invisible walls or you make every map a box canyon where you have mountains everywhere that you can't climb or you make everywhere inside a building. From a technical aspect they have to have cutoffs and limits otherwise it would be loading hell. That being said I'm glad that Bungie isn't as prolific with their soft kill zones as they were in Reach. I'm not kidding there was a firefight map with light posts with soft kill zones on them. Light posts. Tops of easily scalable buildings, etc. It was basically a rail shooter. I even made a joke forge map called the halo reach experience where you had to navigate a maze of soft kill zones. That's dumb. When they put soft kill zones in the Templar well I had a traumatic flashback to that nonsense. Second is advertisement. General rule of thumb now is that "open world" means nothing at all. It's just something you say about a game that isn't literally on rails. Basically destiny's patrol zones can't be opened up beyond what's there because everything else is a picture. Hopefully with destiny 2 not being launched on four consoles we can have larger spaces and not rely as heavily on transition zones to offset draw distances between consoles (that's why between every area there's a canyon or a corridor building, it's to offset loading times to make you take time getting to zones so they can load and you don't see too much at once).