Tony Abbott’s imminent ministerial reshuffle has become a serious test of the Prime Minister’s leadership. Will he wimp it, or make the most of the opportunity?

Now that the Independent Commission Against Corruption reports affecting Arthur Sinodinos have been delayed from January to March at the earliest, Abbott has concluded the government does require an assistant treasurer to help with the May budget.

Sinodinos stood aside from that post in March; Finance Minister Mathias Cormann had Sinodinos' work added to his own load. Cormann is a strong performer but to have him continue any longer in two jobs would have been ridiculous.

Admittedly, the situation is hard on Sinodinos. He’s out of the ministry on pragmatic grounds before a proper judgement can be made on whether he should have had to leave on ethical ones. Abbott’s inclination for a long time was to stand by Sinodinos until the matter was clarified, but the changed timetable made that unsustainable.

The word from Abbott’s office for months has been that in the event of a reshuffle triggered by the Sinodinos factor, Abbott wanted minimal changes. That is what some sources believe is likely to happen but others are expecting wider moves.

Under the minimalist scenario, the probable course is that a parliamentary secretary – the favourite is Josh Frydenberg, who is praised for his work on deregulation – is promoted to assistant treasurer, or to take the job of a junior minister such as Sussan Ley who would move into that spot.

Assistant treasurer, incidentally, is a plum job. While it has been in the outer ministry and thus Sinodinos was disappointed with it (having earlier been given the nod by Abbott that he’d get finance), it is a great training ground for an ambitious minister. It provides an insight into all areas of administration and – very importantly – a seat on the expenditure review committee, taking its incumbent to the heart of government.

With a minimalist reshuffle, the idea apparently would be to have a more substantial one at the end of next year.

Why anyone thinks that would be the sensible course is unclear. The government needs the best possible frontbench now. It doesn’t necessarily benefit from an overhaul months before an election, unless you believe a reshuffle is more about cosmetics than increasing the capacity for substantial work.

If things roll down the minimalist road, what will be the nature of the verdict? Harsh – that Abbott has missed the chance to boost the team’s talent, and the representation of women.

Abbott fears that anything too extensive can be destabilising, creating critics and enemies. That’s true – but acting too conservatively also risks a backlash, not just from the commentators but internally.

And he really has to address the gender issue. What is the use of putting that off for a year? Only one woman is in cabinet and they are sparse in the ministry. Abbott was heard to opine a while ago that he would like to promote Michaelia Cash, a junior minister, into cabinet; Ley also has a claim to a cabinet spot. Karen Andrews, a Queensland backbencher, has a case to get a parliamentary secretaryship.

No discussion of a reshuffle can avoid the perennially embattled Defence Minister David Johnston. Whatever decision is taken about him carries difficulties. His critics are many, but moving him would be seen as putting blood in the water.

When pressed in Parliament recently to say whether Johnston would be defence minister when Parliament resumes in February, Abbott dodged.

Deputy Liberal leader Julie Bishop is a strong ally of Johnston – who’s had trouble with Abbott’s office - and would no doubt speak up for him if asked.

If the reshuffle is widened Immigration Minister Scott Morrison will be seeking to expand his territory or change empires. Having stopped the boats, Morrison has for some time wanted something extra or different to do, to the frustration of ministers whose areas he abuts.

What is particularly unfortunate about this government is that it has a lot of talent outside the frontbench that is sorely needed inside it.

In opposition Abbott was loath to change his line up; coming to government he made some alterations but avoided a sweeping overhaul.

The election brought new faces to the parliament; now these people have settled in, the best of them have claims for promotion. When economic messaging is a problem, why not make use of Christian Porter, former West Australian treasurer? He hardly needs to “serve his time”, despite Abbott liking people to do that.

What would happen if Abbott put aside his caution and made some bold moves? Yes, losers would gripe. But with a seriously revamped team would the government go into 2015 in a better position? Without doubt.

Michelle Grattan does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.