I think it's always been like that (the recipient having to take the evidence into Australia Post), mostly because they have all the evidence that AP require to determine the claim, plus they are (legally) the owner of the item at the time it passes into AP's hands.

Sometimes it's meant the buyer has actually been compensated twice - once by the seller, and again by Australia Post. I know there have been some that return the refund (or replacement) to the seller, but others have kept both.