As I now do each election (2014, 2011, 2008), below, the results of the 2017 general election if there was no threshold:
National – 54
ACT – 1New Zealand First – 9
TOP - 3
Māori Party – 1
Labour – 44
The Greens – 8
(total 120 MPs)
Obviously, voters would behave differently if there was no threshold, but these numbers show that even with the strong disincentive that the threshold gives to people considering voting for minor parties, there are four MPs worth of voters who have been told that their views and interests are unworthy of being represented in Parliament.