Good news for MMP today, with a UMR Research poll showing 48% of voters wanting to retain it, versus 40% wanting change. But the interesting bits are in the details: only 19% of under 30's wanted change, versus 58% of over 60's (so it really is the dead hand of the old reaching out to strangle the future). As for the most likely opponent, no-one likes John Key's favoured Supplementary Member system - which isn't really surprising as it is the worst of both worlds (all the unfairness of FPP, plus list MPs!) So the likely opponent if there is a vote for change is FPP, with STV (!) a close second.
That's something we can be confident about. MMP can beat FPP. The unfairness of the old electoral system, the way it gave disproportionate power to a tiny clique around the PM while shutting out all other voices, and the way it reduced most elections to a battle for a few key marginal seats is part of our historical record (and seared into the memories of those of us who remember the 80's and 90's). While the grumpy old may be uncomfortable with seeing other faces and hearing other voices (yes, MMP means people other than dead white males get to sit in Parliament), I'm not sure they'd want to go back to that.