In 1993, the New Zealand electorate voted for a more democratic electoral system. One of the reasons was disgust at a system which allowed parties to govern without majority (and in some cases even plurality) support. Another was a desire to castrate the executive and prevent small cliques of idealogues from imposing their demented vision on the country. A third was a desire for a fair electoral system, which saw all parties receive representation proportional to their support, rather than magnifying differences to give disproportionate results and excluding all but the two main parties. Since then, MMP has given us democratic government, better representation, greater diversity, and greater legitimacy. And now National wants to roll it back.
This shouldn't come as any surprise - the right has always hated democracy, seeing it as a check on their power and privilege (not to mention a fundamental challenge to their inflated and inegalitarian view of themselves). And MMP has posed particular challenges for National - having to have friends and make compromises in order to gain power was always going to be a problem for a party which sees itself as the "natural party of government". But in a democracy, parties which have trouble getting elected should change their policies in order to appeal more to the voters. Changing the electoral system to give you an advantage just isn't on. That's the sort of thing shitty little autocrats like Berluscioni and Chavez do; we shouldn't allow it to happen in New Zealand.
As for Peter Shirtcliffe, I'm not surprised to see him rear his ugly head on this issue again. He tried to buy our constitution once in 1993; we shouldn't let him do it again.