I agree about the standards at the Melbourne Westin, and received a similar corner room with huge spa bath, etc. My take on why these properties are far better than US and Canadian counterparts is because they cater to an experienced traveller who for the most part was weined on the standards found in major Asian cities. I think the staff at these hotels in Australia -- and I would include the Hyatts and other chains too -- use this standard. It is a bench mark that is unknown to staff working NAmerican hotels, and the vast majority of their customers never have either. So with low expectations, NAmerican properties have little to strive for. If you are looking for similar standards in our part of the world, these will be found at Four Seasons and RitzCarltons, along with St.Regis and InterContinental and similar top tier properties in major cities. In this, most Westins in NAmerica are not the place these top tier travellers stay.
I was struck by this reality in the 80s when I started to travel extensively throughout the Pacific rim. Staying at hotels in NAmerica was a let down ever since.