... And how is and expantion of an enviroment a bad thing? America is post-Apocalyptic. American stages are large and vast. An open world setting is the logical way to see the game. You can still tell a deep story without it being linear. An open world gives you more options on how to handle getting from Point A to Point B, with extra engagements in the middle. A sandwich.
All Fallout games are open world. It's just that the two latest ones are much smaller (in map size) and instead detail every inch of the wasteland. I'd prefer if we could get maps that cover an entire state again, and then we'd get a big bunch of smaller playable maps (nodes) that they can fill and detail with stuff (kind of like the size of the DLC maps, some smaller if it's just a cave, raider holdout or nuka cola factory, and some bigger like if it's a settlement or a forest kind of like Point Lookout.)
And
inbetween these nodes, there would be procedurally generated wasteland, like just a miles of desert, roads, small gas stops and mountains, so you have the option to travel between A and B in real time if you want and still get the feeling of a desolate wasteland and a huge open world in 3D, and then there would the option that when you exit a "node" you can travel on the map, in real time, from point A to B and you can speed up travel by having a mount or a vehicle, and now and then you can get random and special encounters as well as smaller nodes showing up that you can explore (say that nuka cola factory I mentioned). [/worlds longest sentence]