I'm very curious, in all of these cases, what the replacement will be and even if there will be a replacement. I mentioned that to my wife (we're Canadian), and her response was why do we even need a head of state if we have a Prime Minister? And I'll be honest, I didn't have an answer.
Props to Australia for taking the first step and making it not part of the citizenship oath. The other ties are still there but at least you are not making people swear allegiance.