To me - Zelda quests have purpose. It's not just about passing one room and going to the next.. the dungeon is a puzzle and you have to solve it. Like Zelda, main quests give you a heart and an item, and through the dungeon it's that item that helps you get to the end - and to the next temple. Our overworld wont be all open for people to roam, you will need to progress through the story and get the items to be able to get to other locations.