There's a lot of evidence to say that Principled Negotiation is a great way to make decisions that are both wise, and inclusive. Inclusiveness matters. If TOP is to fulfill its potential over the coming years, then even people who didn't vote for TOP need to see TOP seeking to understand their needs and interests, and caring about those needs and interests in formulating its policies.
For example, consider a farmer who says "We don't need to care about cow farts, because global warming is not real". An evidence-based party won't agree with the latter portion of that statement. But, behind the factually-incorrect statement, are the underlying needs and interests of the farmer. It is perfectly valid for the farmer to be concerned about how climate change regulation may impact their livelihood. A party like TOP needs to acknowledge the validity of that concern. We need to show care and respect for all New Zealanders, no matter what their political viewpoint, and we need to factor all of their concerns into our quest for evidence-based solutions.
The answers aren't always easy (if they were, TOP wouldn't need to exist) and there will always need to be decisions made that some people are not happy about. But they will be less unhappy if they know that TOP genuinely understood their concerns, exhaustively searched for solution options that respected those concerns, and transparently shared the evidence in those cases where the concerns could not be satisfied.
(For more on Principled Negotiation as it could be applied to NZ public life, see http://agilekiwi.com/off-topic/fixing-the-engine-of-public-discussion . That's my own blog post, and I know its bad form to link to yourself, but I couldn't think of a more NZ-relevant description of Principled Negotiation.)