The government's proposed changes to citizenship for dual nationals would allow a minister to cancel a dual citizen's citizenship at their own discretion, and it would not allow appeals to the court. If someone is not a citizen, only having a visa enables them to stay in Australia. Even if they have a visa (and why would they?), it can be cancelled by the same minister, so they could potentially be deported or at least moved to detention, held incommunicado, before anyone knows what's happening. This is remarkably dangerous.
The Liberal Party have clearly included in their talking points a lot of emphasis on protections, but let's have a quick look at them. As an aside, Labor has also been working through how to word support for this. The bill would allow for judicial review. I don't believe that this is because of the government's concern for the rule of law; I believe it's because whenever, in the past, Australian governments have tried to exclude it as an option, the High Court has found a way to re-include it, either by saying the government didn't word the legislation effectively enough to exclude it, or that the government couldn't exclude it because the Constitution directly allows for some petitions to the High Court that the government can't legislate away.
But, put simply, judicial review only allows a person to challenge whether a decision was made properly; it does not allow a person to challenge whether a decision was made reasonably given the facts, i.e. it does not allow for a merits based appeal where the affected party can question the fairness or accuracy of the decision, except in very limited circumstances. Typically, the minister's decision would stand unless it meets a really high standard called Wednesbury unreasonableness, which is defined as:
"A reasoning or decision is Wednesbury unreasonable (or irrational) if it is so unreasonable that no reasonable person acting reasonably could have made it."
That's not very illuminating, so in practise, you need to prove that the decision was unreasonable beyond belief. Luckily, reasons for (most kind of) administrative decisions need to be made available, so that gives some fuel. In SZMDS, a homosexual man was deported back to Pakistan because the minister didn't believe he was really afraid (and the federal court judge didn't believe he was really gay (despite strong evidence)). That's the kind of stuff that doesn't meet the level of unreasonableness that would allow a successful challenge.
Even if a decision was challenged successfully, the typical result is that the minister just needs to remake the decision. Much of the time, they make it differently with a different result, because they know they're being watched, but we've seen how belligerent this government is with political decisions; they'd just make the same decision, maybe for better rationalised reasons, which is what Scott Morrison tried to do in S297.
In addition, the minister's reasons, which would normally be accessible to the formerly dual citizen, would likely be exempt from being made available, as the documents would probably have been prepared for cabinet, or be related to national security (as we've been told is the purpose of this legislation) and are therefore exempt from the Freedom of Information Act. All the safeguards that the Abbott government have given are a smokescreen.
So, I, a person who was born an Australian citizen, who has spent most of my life here, but commonly speak out against the policies of both the major Australian parties, should rationally fear that at some point, my citizenship could be revoked on a whim. That's a pretty bad chilling effect against my continued involvement in the political process. If that seems like an unreasonable position because the government has said that the bill is only meant to affect people who leave the country to fight against "our interests", consider that they don't feel so strongly that they'd actually put that as a requirement into the legislation. As usual, with civil-liberty-encroaching legislation, we are told that there are protections, but they're merely spoken platitudes, unwritten and unbinding.
My job involves finding edge cases that allow for a well meaning rule to be exploited, but I don't pride myself on finding this one, because it's not subtle. To any of these lawyers in power, assuming they wrote their own essays and sat their own exams, it's obvious. Obvious to the point of being clearly intended. All these laws to protect us from the way-of-life-changing effects of terrorism, and it's always the major party politicians destroying the rule of law and freedoms we hold dear.
 Associated Provincial Picture Houses Ltd v Wednesbury Corporation (1948) 1 KB 223
 Minister for Immigration and Citizenship v SZMDS & ANOR  226 ALR 367