I read
@ren0312's post differently to you - mainly that he is saying that it's likely that the way the NZDF is heading it will resemble the Irish Defence Force in terms of scope and overall capability. Basically a glorified police force. And I don't see how you could argue with that point - while the NZDF is bigger and it's geographical responsibilities are not comparable, over time it has progressively been degraded.
As to his second point; hasn't the US and Australia effectively provided external defence of NZ for the past 20 - 30 years? Well, they + geography. Yes NZ has it's own government and strategy, it's own diplomatic relations (including ones regionally that are superior to us and we rely on heavily because of that), and contributions to military operations in the region and Middle East, but it doesn't really have the depth or offensive capability to defend the nation. I have sat in meetings where the feasibility of offloading significant parts of remaining capability to Australia were debated - and the meetings were requested from NZ, not us.
I'm not questioning the people - I have in the past and will in the future serve with NZDF personnel and from my point of view they are no different to Brits or Australians - utterly dependable, highly professional and look out for their mates. But the successive government policies, for good or for bad, have made the NZDF much more constabulary (ie, like the Irish Defence Force) than military (like Australia or Singapore).