mm 4.3 just introduce 2d system to make games in 2d, not to make user interfaces. So that means that if you don't use ngui you will have to implement your own widgets, like buttons, inputs, slider, progress bar, list, etc.
Until the new UI system of unity arrives, unity 4.3 will help you to make 2d games, and NGUI will help you to make the user interface for your games