The Witcher 3 is not really open world though. It mainly consists of a couple of separate regions that have their own map.
To say that Witcher 3 is not open world is just nitpicking. 3 of the areas are big enough to e their own open world game themselves, and the other two are still pretty good sized. I hardly call hitting a loading screen like 5 times in a game as not open world.
The fact that you can spend 30 some hours doing quests without having one loading screen, traversing the wilds and going to dozens of towns is open world to me. Having to load 5 areas in the game total is nothing.