At the moment, the states do fund public schools, but the issue about the responsibility of the state governments is that they have to fund various services, but do not have much taxing power as the federal government. As a student of private school, who has been to a public high school, I personally am not a fan of the government funding of private school that charge some $20k or $30k per student. They can, however supplement low cost independent schools who does not make a huge profit from their students.
In your oral, I think it would be good to talk about Gonski model of school funding, which was proposed by labour in the Rudd-Gillard era. This model proposes a more, needs based funding model, as opposed to funding more private schools that do not take many disabled or low social-economic status students, through public money. (Under Gonski, private schools still get public funding, but it is cut off at a certain profit for the school). A negative for Gonski is that it does cost $6.5 billion dollars and we are currently in the budget deficit.
But I cannot really suggest anything unless I know the stance of your oral, and wether you're for or against it.
You could argue that Turnbull is shifting the responsibility of educating the people from the federal government to the state government. It is unlikely to be consistent in quality, across the 7 states and territories across Australia. It pits state against state, which can be good or bad, depending on how you look at it. It often means that the poorer states would have less money to practice public education and healthcare, meaning that the poorer state remain poor.
Remember that the state government does not have much taxing powers (compared to the federal government), so they could find funding these areas difficult. I think in terms of state funding, I think you may need to take a look at the US model, where the states are fully responsible of funding the public schools. That being said, you do not need to propose this model, but propose another one and still argue that the state should be responsible for public schools overall. Also, you could be for Gonski, and for state being ultimately in charge of funding public schools.