You're reading too much into this. There is no mention of overlying "control zones", although I could see that being logical (although I can't think of a need for a broadcast area
under one of the current CTRs). For some years,
large CTAFs existed over the top-end, in WA and the NT. The NAS ideologues had them removed a couple of years ago because they didn't exist in the USA. Guess what, they
do work well and so CASA is re-instating them.
Yet another example of "I think they do things this way in the USA without really understanding it but let's copy it anyway" is not always the best way of making airspace policy (along with the circuit calls/verbal diarrhoea that was introduced at the "urging" of the same ideologues a couple of years back).
So, really, nothing much has changed this time round; the only change being an improvement/return to what was previously in place.