The government that was elected in that campaign is now gone; most of its ministers have retired, including Steven Joyce, the former finance minister whose retirement from Parliament in 2018 opened up a seat in Parliament for Willis, and former Transport Minister turned leader turned finance spokesman Simon Bridges, whose retirement opened the portfolio vacancy Willis has now filled.
The current National leadership is light on former ministers, with many having departed, but is not entirely disinherited itself from the previous National government - with Willis and her frontbench ally Chris Bishop both having served as staffers during the Key years.
Speaking to the Herald and the On the Tiles podcast, Willis describes the staffer experience as an "incredible apprenticeship in terms of working out what works and what doesn't".
Not, not the party of Key and English
By chance, Willis began her Parliamentary career in the office of Bill English, who had already been a finance minister of a kind (the role English occupied was "Treasurer", a portfolio since rolled back into Finance, and he only held it for a few months before National lost the 1999 election).
By the time Willis got to Parliament, English had risen to leader, lost the 2002 election, and been rolled by Don Brash. English became education spokesman, which is where Willis met him.
"In my interview, I was asked which area I was interested in, and I said 'education'," Willis recalled. "That paired me up with Bill English, who at that time was opposition education spokesperson."
Willis never really looked back during the Key-English years.
"He [English] of course ended up being deputy leader to John Key and I ended up being his senior advisor," Willis said.
Perhaps unsurprisingly, Willis is not so keen to talk about the parallels between now and the Brash years: an opposition in its second term finding its feet and lifting its polling to level with the incumbent government.
"There was a huge comeback story there," she said, before moving to the more favourable comparator: the successful 2008 campaign.
"When it came to 2008, the real difference was ... people saw in John Key and Bill English a team they could believe in.
"Leadership really matters and people ultimately look to their leaders," Willis said.
Social investment
Willis is now the custodian not just of English's finance portfolio, but of social investment, a targeted approach to welfare that evolved in the later years of the National government and was strongly associated with English.
On taking office, Labour declared itself agnostic on social investment, it kept the Social Investment Agency (renamed to the distinctly Ardernish "Social Wellbeing Agency"), and shifted towards a more universal approach to welfare, "proportionate universalism", in the words of Jacinda Ardern.
Willis does not recall the current Government's treatment of social investment with any Labourly kindness: "They killed it," she said.
Now, National wants to bring it back.
Willis said the approach is about "how can the Crown use its levers and use its investment to genuinely transform people's lives".
This does not necessarily mean a walk back from universalism. Willis thinks Kiwis expect universal access to things like health and education.
"In New Zealand, I think we have a real appetite for a welfare safety net - we believe typically as taxpayers that there's a role for the government in protecting our most vulnerable and ensuring that kids get an equal chance in life.
"Yet successive governments, having spent billions of dollars in the social welfare system, the education system, the health system - we can't honestly say that we have achieved that equal opportunity.
"Social investment is about saying what are the interventions that the state can make powerfully now that will actually make a difference to the way people's lives unfold," she said.
Social investment, however, is about looking at areas where the state could do more to lift people into a better life with targeted interventions: people like teen mothers, people in prison or likely to go to prison, or people in welfare-dependent households.
Willis said she caught up with English for a zero sugar Coke "in the past few weeks", prior to getting the finance job. The relationship between the two appeared to strain last term over the twin issues of abortion and end of life choice (backed by Willis and opposed by English). Willis said she would "continue to pick up the phone" to English, despite that opposition.
"He's a great thinker," Willis said.
Finance
Willis is no slouch in opposition. As housing spokeswoman, she managed to detoxify the issue of housing for National to the point where a recent poll showed more people trust National to fix housing than Labour. She served on Parliament's Finance and Expenditure Committee, grilling officials from Treasury and the Reserve Bank.
She is still new to the finance portfolio, however.
Willis told the Herald: "Right now the Government is around 25 per cent of economic activity", when it's actually about 31 per cent if measured by spending, climbing to 35 (with a long-run average of around 27-30 per cent), and she wasn't entirely familiar with the party's policy on what to do with the Reserve Bank's monetary policy remit - the instruction the finance minister gives to the Reserve Bank Governor.
National has had a longstanding policy of reversing Grant Robertson's decision to give the Bank a dual mandate, asking it to focus on controlling inflation, as well as maximum sustainable employment.
Since the pandemic, critics have said the Bank's focus on employment has meant it went too hard with its monetary policy response, with terrible consequences in the housing market.
Willis said National would "look at" the dual mandate.
"One of the things we've raised questions about is whether the dual mandate that's been given to the current governor with the focus on maximum sustainable employment as well price stability, whether that has perhaps influenced some of the decision making that has occurred," Willis said.
Actually, the party policy isn't to "look at" the dual mandate, it's to get rid of it.
Willis later said National would "remove maximum sustainable employment from the mandate and return to something closer to the previous mandate, which worked well for 30 years before Grant Robertson decided to change it".
"The exact wording of that is what we need to look at," she said.
One area National does not currently have policy is what to do with the Government's decision to ask the bank to support more "sustainable house prices" - a move the Government made as the housing market spun out of control in 2020.
Willis wants to look at this too.
"The question for me is, 'what effect has it actually had'.
"That's the question that I want answered first and I don't think it's abundantly clear right now. I don't think it has changed decision making at the Reserve Bank."
Simon Bridges
Shortly after his exit from the finance gig, Bridges joked on the Spinoff's Gone by Lunchtime podcast (itself named after a Don Brash gaffe, by coincidence), that he would feel a "twinge of envy" seeing the next National finance minister knowing that he could have been "much, much better".
Asked to respond to the gag, Willis wasn't keen to dig in. The new National isn't keen on sniping between MPs - even if it's in jest.
"I think that is a good thing - we should all have our feet held to the fire," Willis said.
Instead, Willis shifted her (very clear) recollection of that podcast to other advice from Bridges, which is to keep the portfolio simple.
"Something that Simon has given me is an incoming piece of wisdom ... 'do keep it simple'.
"Ultimately, as the finance spokesperson you can spend a lot of time talking about multifactor productivity and GDP growth and, yes, you do need to be across that - but how does that translate for a typical family when they're working out their budget round the table, and what difference will it make for them," Willis said.
On the Tiles is the New Zealand Herald politics podcast. You can find it on iHeartRadio, Apple Podcasts, Spotify or wherever you get your podcasts.
