Discussion paper: National Registration Framework for Building Practitioners

Mutual recognition of registration in different jurisdictions still imposes the cost and paperwork of registering in each jurisdiction. Having the same baseline qualifications is a good starting point, but for a structural engineer to need to separately register (and pay registration) in every state that their clients are present is an impost on them that seems to be driven wholly by paperwork rather than providing any real benefit.
I suggest that an engineer can apply to be registered in a state by providing that they are on the NER (or another register), and that the state registration isn't an additional fee for the engineer.

If you are required to be registered to be an engineer, it might assist. I'm not convinced, as engineering as a whole is still seen as a commodity where the minimum fee possible is paid, and engineers gladly cut each others throats (metaphorically) to win work.

Each state will implement this differently, and engineers will not have deep appreciation of the differing risks and requirements of each state. Unless there is model legislation enacted at each state, and the disciplinary processes are mirrored, each state will make their own preferences, leading to less certainty as to how to proceed in a manner that will comply.

We are already required to design to the NCC. If we aren't already, then a register wont change that fact.

"Registered structural professional engineering designer" is a very cumbersome regulated title. I can't see it being something that will be useful to the general public, or be something that will add any great value compared to any one of the many post nominals that a structural engineer might already carry (CPEng, NER, MIEAust, RPEQ, VBA)
Is it not possible to just restrict the use of "Structural Engineer"?

no