This follows greater scrutiny of the republican model being put. The wording of the referendum is of course crucial. This version would probably win. Only diehard monarchists want a King Charles of Australia. Smart observers think this proposal would lose.
Australian voters have a history of rejecting referenda proposals.
But the real problem is that it is one thing to agree the Australian monarchy should be replaced, it is another to agree what to replace it with. There are many who don't agree the monarchy should be replaced, notably including PM Howard. Under this model, the President would be appointed by a two-thirds majority of the Commonwealth Parliament. This model was endorsed by a constitutional convention held early in 1998. Two other models were considered but rejected at the convention.