After using last November's referendum to 'kick the tyres' on MMP, voters now have the opportunity to give it a more thorough tune-up.
Legislation that enabled the referendum also empowered the Electoral Commission to undertake a review of the workings of MMP if a majority opted for the status quo.
The public consultation process is under way, and while much of the attention so far has focused on the threshold, the other contentious issues under review are all associated in some way with the status of list MPs.
This is not surprising when viewed against the backdrop of 140 years of first-past-the-post, when all MPs were elected individually from distinct geographical constituencies.
In contrast, the concept of a list MP that somehow transcends electorate boundaries still appears foreign to us (and often the MPs themselves).
Under MMP, the list is the mechanism that helps deliver seats to parties in proportion to their share of the nationwide party vote, something that the majority of New Zealanders have decided is important after all.
Yet after six elections, list MPs still face an identity crisis, exemplified by the issue of whether candidates should continue to contest both list and electorate seats.
In recommending the adoption of MMP in 1986, the Royal Commission on the Electoral System was attracted by the potential for some list MPs to be freed of electorate duties to focus solely on national issues.
However, the Commission was also mindful of creating two different classes of MP, so supported dual candidacies as a way of blurring the lines between them, enabling electorate candidates to be returned on the list if they lost their seat.
This is where two contesting values collide.
On one hand, there is a perception that the path to legitimacy for list MPs is to establish ties to an electorate. On the other, what voters valued about FPP was the ability to remove a sitting electorate MP.
Under MMP, that MP may still return to Parliament if they have the lifeboat of a high list ranking. This can even occur between elections, if another list MP resigns or wins a by-election.
A study of the turnover of MPs elected under MMP in Germany from 1949-2005 confirmed that dual candidates had longer careers than list-only candidates (although the longest-serving MPs solely stood in electorates).
Whether voters see the list as a legitimate way of ensuring the retention of capable representatives or a perversion of the electorate's will depends on their perceptions of any given MP: one voter's hero is another voter's hack. At least a losing electorate candidate who returns via the list cannot claim to be the Member for that seat.
If dual candidacies were abolished, the way we are represented might look quite different. The lists for the major parties would no longer reflect the balance of personnel within them, when you consider that four-fifths of National Party ministers are currently electorate MPs.
As the mechanism that has helped women and ethnic minorities improve their representation under MMP, the list may become a ghetto for such candidates if the opportunity to contest an electorate became riskier.
Minor parties may decide to contest fewer electorates as their top candidates focus solely on the list, and there would also be less incentive for list MPs to set up electorate offices.
Although incumbent electorate MPs would welcome these changes, it would lead to less choice for constituents, and list MPs who are less grounded by their constituents' concerns.
There is also some democratic value (and schadenfreude) in encouraging as many candidates as possible to face the scrutiny of local "meet the candidates" events.
So if establishing connections between list MPs and electorates is deemed more important than the possibility that the list is used to return unpopular MPs, should it be strengthened further?
An editorial in the Herald last month suggested that a party's list seats should be filled by its highest polling losing electorate candidates.
The Royal Commission also considered the "biggest loser" proposal, but concluded that votes for losing candidates are subject to a range of variables (e.g. support for minor party candidates) that might bear little reflection on their worthiness as a candidate.
In any case, most parties already limit the number of list-only candidates, formally or informally. They recognise the incentives in both heading the list with their most senior electorate MPs, and encouraging their list candidates to contest electorates.
It's up to parties to decide how they balance ability, experience, diversity and renewal on their list, and then it's up to voters to judge them on that through their party vote (and they have).
In that sense, we elect all MPs, and regardless of whether they are a list member or the Member for Helensville, they are all Members of Parliament.
* Dr Stephen Church is a Wellington-based consultant who has previously worked as a ministerial advisor, and a university lecturer and researcher in New Zealand politics