Ever since the New Zealand electoral system was changed from a British (and US)-style First Past the Post (FPP) system to a Mixed Member Proportional (MMP) modelled on the post-war German one, the major parties, who have seen their easy majorities lost to a plethora of upstarts in Parliament, would love to turn the clock back to a more majoritarian system away from a proportional one.
Matt McCarten opined on this berating the Business Round Table, a New Zealand free market think tank, for proposing to do away with the separate Maori seats as it causes over-representation of Maori in parliament. Under FPP there was an over-representation of white males in parliament. But this has not really changed with MMP since electorate seats are won under FPP rules. The diversity of parliament comes from its proportional aspect of the electoral system. His argument that right wingers only want to do away with the brown seats forgets to add that a party running in the Maori seats doesn't need a majority vote to win it, only a plurality will suffice, as is the case in all other electorate seats
I am much in favour of MMP, but the proportionality can definitely be improved on:
1. The obvious one is to abolish electorate seats altogether, both general and Maori, and move to a completely proportional system.
2. The threshold then would be 1/120th of the votes cast for a party list. Since there would be no electorates there would be no one-man-band parties with limited geographical appeal. Small parties would still exist if they can appeal to 120th of the total electorate, which in my opinion is preferable to appealing to the largest minority in a current electorate (since FPP still applies there under MMP)
3. Maori (and pakeha) would be able to choose between more than one Maori party instead of having to rely on the current "Maori Party" pretending to speak for all Maori. The current situation in Maori seats is like the National Party pretending to speak for all New Zealanders in non-Maori seats! I can understand the Maori party prefers the in-effect FPP structure of the Maori seats: it doesn't need an absolute majority to win them, a relative majority will do.
4. The two vote system can be simplified to one list vote, with a published ranking of candidates. You either vote for the total list accepting the party ranking, or you vote for a candidate on the list to push his/her placing higher (those votes would be counted to re-order the seat outcome for list members). There could be more Maori MPs under that system than there are now, so nobody should be fearful of losing the "guaranteed" Maori representation. Even pakeha could vote for a Maori party!
5. This list-only proportional system would move away from personality politics and focus the minds far more on actual policy and with possible coalition agreements, workable and pragmatic majorities that are far more reflective of the electoral will.
There is also discussion on this issue (and possible future referendums) on Public Address.