It sees the world as Nature, and leaves out the meaning of the world for Dasein. Not unlike the concept of Being, the phenomenon of the world has escaped the tradition. Heidegger wants to leave this concept of the world, and show the world in an existential way. The world is not the material, physicality of the planet. The world cannot be found in Nature.
Nature is an element of the world, a mere characteristic to be encountered in the world.
The world is a characteristic of Dasein. The world and Dasein are a unity. The world is not the Cartesian extended substance. By having this as the concept of the world, the world as a meaning for Dasein is overlooked. Existentially and ontically, the world is where Dasein lives, resides.