The thing is finding the right balance and making the game unique. Destiny will have you come back. This is what a game should do is have you have a great experience of story, action and music not to mention all the work that goes into making that world a solid real world. A game that has a open sandbox letting you explore it is just interesting fun as you learn in depth more about it. Skyrim or Fallout are examples of this. Each story has its key moments.