In summary, the 183 day rule doesn't look good for expats.
Interestingly, my accountant who I used to lodge my tax return each year raised the subject a few years back that if living overseas earnings generated in Aus. could be taxable - but appeared to be ignored if you kept your head down, and as I lodged a return each year using a local address we ignored it. Seems the current idea is to now toughen up and formalise it.
For me, it makes no difference as I'm back in Aus, but given the opportunity to voice my opinion on it I would be dead against it for the average low income earning pensioner.
My gut feeling is it will come to pass - so expats who will be affected need to be aware of it.