I once did a debate in university on this controversial topic. We won the debate and these were the main points included:
>It would set a new tradition for Australia
>A Study taken in 2002 at UQ ( University of Queensland ) indicated that nearly 75% of people surveyed believed that the constitution was old and need to reform and include a bill of rights.
>The constitution doesn't limit rights. It is open to interpretation. Unlike the constitution
Thats about it. That should help