At least something like "adopt the Australia/Canada model" is easier for people to understand, because while a radical change, they can point to somewhere else that has been doing it successfully for decades. Incremental tinkering with the current rules can make unengaged people mentally switch off by comparison; radical changes can be easier to understand because they can be simpler to explain.

I think one problem with the Australia/Canada model, is even though constitutional monarchy isn't essential to it – both countries could arguably function just as well if they were federal parliamentary republics – many Americans mentally conflate the parliamentary and constitutional monarchy aspects. If eventually either or both countries became republics, that would probably make it easier to sell the idea to Americans.

Germany is a living example of a federal parliamentary republic – but the language barrier limits its accessibility as a model for Anglophone emulation.

One backdoor way it might happen – although no doubt quite unlikely – would be if Alberta seceded from Canada, got admitted as a US state, but kept something close to its current parliamentary system.