I wouldn't call the constitution a relic, it is, albeit imperfectly, a functioning document, that maintains a certain cohesion in this country. Calling it a relic somewhat undermines that important use to the nation. I don't argue with the characterisation of Colonialist. It very much was set in these terms.

Colossal centralisation of power is an odd thing to claim, and possibly ill-informed.

• The primacy of Parliaments, made up of many people, over Governors, single people, is very much established in this country but even the Governors retain some power away from Parliament in limited circumstances, think of GG's power of dismissal,
• The system of exclusive powers to the federals with the states retaining all other powers is an extremely important partition of power,
• Each state retained their own Courts, Parliaments, and Governors and much of the public service supporting those remits separately from the Federal government, who also gained the full set of those positions to represent the country as one.

The country took lots of opportunities to ensure the dilution of power. And much of that is contained within the Constitution. So i would say it protects the devolvement of powers from any one body.

'Inalienable rights' has been considered by many in Australia. I think the closer you get to the detail the less atractive that proposition becomes. People have a responsibilty when they speak, 'inalienable rights' has proven to lead to a reduction in peoples calculation of their own responsibilties when speaking. The provisions for this in the US have been an example where such a rigid code can lead to poorer outcomes. The calculation here is, our system gets protection of speech about the same as places with the explicit right, but without some of the adverse consequences, because the protection remains somewhat fungible. Fungibilty is important to courts where they may wish to distinguish from precedent for legitimate reasons.

'Modern' should be left as a concept of the Post WW2 period. We are, as a whole, more like our ancestors than the word 'modern' allows. Modern has become a hopeful term that things are 'better today than yesterday', and thats not always true. Modern clouds the nuance. This isn't a bad or good thing, only an observation that the term 'modern' or 'life today', etc, is a mental separation from history that has proven unhelpful.

I never said the constitution or the nation is progressive, nor should it be assumed that is the goal. There are people who aren't progressive in this nation, just as there are progressive people. A well functioning founding document should seek to balance the views of the many without trampling the rights of the few. Thats not a progressive sentiment, thats a utilitarian sentiment. This is a strategy to stop endless cycles of violence/repression, allowing people to live in reasonable liberty. A strength of the Constitution is that it isn't particularly prescriptive.