Wills' damning report into how children in state care are treated (neglected), means that her report will have a much easer ride in terms of political acceptance.
When her report is released, it won't be just the plan of a trusted servant of the Government.
It will be a plan to address what Wills said was not only ineffective, but actually harmful to kids the longer they stayed in care.
Wills has credibility with the groups that might be tempted to oppose new ways of social service delivery that Rebstock may propose.
His efforts to highlight child poverty last term by setting up an expert advisory group to work on solutions got under the skin of Government.
He and his experts succeeded wildly in highlighting issues of child poverty and inequality and child poverty became central themes of the Labour and Greens campaign.
While the Government did not say at the time that Wills was straying from his core business into politics, they thought it.
He returned to "core business" with this report.
It has had impact as much for what it couldn't tell us (why 1000 of the 17,000 kids in care in 2014 were no longer in care) as for what it could (117 abused while in care).
But damning as it was, you could almost hear the collective sigh around the country of CYF fatigue; yet another report into yet more failures.
There were also equally predictable responses about the need to resource the agency properly, to hire more social workers, to cut down the caseload of each social worker.
I've been hearing about this since 1992 when, as social welfare and housing reporter with the Herald, I covered the first review into the Children, Young Persons and their Families Act 1989.
It was a radical experiment at the time brought in when Michael Cullen was Social Welfare Minister.
It introduced the concept of the family group conference as a key part of finding solutions to both functions of the Children and Young Persons Service: care and protection for kids at risk and youth justice for young offenders, although the lines between both are often blurred.
The 1992 review was chaired by Ken Mason, in between his reviews of the mental health services.
There may have been 14 reviews into CYF as Social Development Minister Anne Tolley claimed this week but they have all focused on different things.
Russell Wills' report stands out for it being mostly a child-centred review and, strangely enough, there have not been very many.
Instead of just inspecting the various CYF sites, he has analysed his findings, looked for themes, trends, and all from the perspective of the child in care.
It wasn't all bad; of the 14 sites he assessed, one was outstanding on all measures and four were outstanding in terms of leadership and directions, results which suggest that workload is not an insurmountable problem.
When Paula Bennett was minister she used a highly consultative process (with 10,000 submissions and plenty of horror stories) to develop the Vulnerable Children's Act, which has given rise to a slow roll-out of Children's Teams (so far in Whangarei, Rotorua, Horowhenua and Marlborough).
Various agencies are supposed to work together with families in difficulty, which are not bad enough for CYF to intervene, but are being slowed down by their own haggling over information-sharing protocols.
Tolley took a different tack to Bennett.
She was not consultative. Tolley became minister last year, having been Corrections Minister. She earned respect in that portfolio for work on rehabilitation and skills for prisoners.
She was, however, building on the transformation of a previously dysfunctional department after a top to bottom review by Paula Rebstock.
She found out what they should be doing, what was stopping them from doing it and how to get them to do it.
Tolley commissioned Rebstock and an expert panel to do that with CYF, and to redesign it with children's needs at the centre.
She didn't want any New Zealand social workers in there, a decision which caused resentment.
Some saw it as cost-cutting exercise. But the social investment approach is not about cutting costs in the short term.
It is about working out where to spend money - possibly more money - to save it in the long term.
And it is about spending money only on things that work.
Rebstock's proposals for CYF are thought to be not dissimilar from the way special education operates, where a child can have access to a range of professional services, depending on their circumstances.
Tolley has already also talked about the need for social workers to be able to access child psychologists or even psychiatrists to help with the complex problems of their charges.
Wills began his State of Care report in January last year, well before Tolley had decided to overhaul CYF through the expert panel.
She did not invite him to be part of the process - although he has set up a group of young people with experience in state care for the expert panel to consult.
With the publication of his report, and the commitment to make it an annual report, Wills has forced himself into the reform process, as it should be.
