I agree that a capable navy, and combat capable airforce are essential for keeping any potential threat away from NZs shores. However, in order to be a regional power in the Pacific and maintain international commitments we still need a well equipped and manned army. A frigate or a fighter may project force, but they cannot hold ground, ie Tonga's international airport, nor can they provide visible security patrols such as in Tonga, Dili or Bamiyan.
A well rounded armed forces needs all three services. NZs main problem is small equipment levels, problems maintaining personnel, and a lack of political will to fund these.
If NZ ever returns to operating fighters, or even a combat capable trainer such as the T-50, we would have difficulty using them in the Pacific region, even if we also acquired tankers. A forward operating base would be needed. Maybe establish a barebones base in Nuie, similar to some RAAF bases up the Top End. A basic security and maintainance force normally, but able to be brought up to opertional standard at short notice. Apart from pure military uses, would be useful for assisting in disaster relief in the Pacific, or even for occassional P-3 deployments.
NZ does have the money, just not the will. If southern SI and sea around Stewart Island become an oil production area may need to improve airforce and navy, just to keep the Bushes hands off