A vote on possible changes to MMP is likely to involve decisions on whether to lower the 5 percent threshold needed to enter parliament to 4 percent and whether to do away with the coat tailing provisions.
Little goes into a bit more detail here. But while he's absolutely right about the unfairness of denying seats to the Conservatives, by linking it to removing coat-tailing, the proposal does as much damage as it remedies. As I noted at the time, at best the Electoral Commission's proposal works out to be roughly as representative as we are at the moment. But in some cases (e.g. 2002) it gives us a much less representative Parliament than we have at present. And that makes it a step backwards, not a step forward. We absolutely need to drop the threshold (IMHO we need to abolish it entirely, or set it to whatever it takes to get a single seat). But as long as there is a threshold greater than the vote required to get two seats, the coat-tailing rule enhances proportionality and representation rather than diminishing it. And if voters don't like the fact that it makes some electorates more crucial than others, the solution is simple: make it irrelevant by abolishing the threshold.
Labour's preferred changes are blatantly driven by self-interest: support their coalition partners while nobbling National's (National's preference for the status quo is equally self-interested, since they benefited from coat-tailing until ACT became a one-man laughing stock). But given the deadlock in the political establishment, bypassing them and putting it to voters in a referendum is fine - its our voting system, after all. But on the current proposal, I will be voting against, and encouraging everyone who wants a properly representative democracy to do likewise.