Could the word "harmonisation" be responsible? Currently we have too many disparate "Governing instruments" in the sky not really talking to each other, and we probably need to trim a few of them away, or at least amalgamate some, as I have said in other threads.
As an example of what I mean, how many different registration categories are there in the air at the moment? (Hang gliders, Manufacturer built gliders, Amateur built gliders, Amateur built GA, Kit built RAA, Manufacturer built RAA, Ultralight RAA, Manufacturer built GA, Historic, etc) Most of these are administered by differing bodies, some of whom have been shown not to be up to the task. Surely it is better to have one organisation (CASA or delegated offshoot) and supporting legislation look after the registration with the various other existing bodies acting as support clubs/general information sources.
The elimination/amalgamation of the RAA flying certificate into the Rec Aviation licence of CASA is clearly the most logical point here. This would ideally be done by upskilling the current RAA certificate issuers to the level of competence required by the Rec Aviation CASA licence.
There is little sense in breaking down the groups into "performance bands" as a way of demarcation of jurisdiction as there are WAY too many overlaps in physical sizes of aircraft with similar performance. Weight only would be the most obvious way. The automotive equivalent is that a car licence allows you to drive a car (up to 4.5 tonne) a truck licence allows a larger weight limit, and a semi-trailer licence allows you to drive a semi. All vehicles actually have the same operation performance (operational speeds, braking capability etc) regardless of how you intend to drive them.
All for the KISS principle........