Listing to some to some of issues raised on, I'll add my thoughts on the various issue:
Personnel Issues
These stem solely from the terms and conditions of service in the Defence Act which allow for release with 3 months notice. This period of time means that NZDF has no time to even recruit, let alone train replacements. The only two viable options are to retain the current arrangements and extend the minimum period of notice to 12 months or shift to a fixed term period of say 4 years (Infantry, Logisitics etc), 7 years (Marine Engineers, Plumbers, Avionics Tech etc.) and 10-12 years for officers (I believe the RN has a 12-year term for officers with a 1-year notice). It is interesting to note from an historical perspective that prior to the change in the terms in conditions in 1977-78 (from memory), the navy was able to maintain the necessary personnel to maintain all its ships except when there was a little munity (for valid cause) around pay issues in 1947.
Speaking of which there needs to be an across-the-board pay rise in the NZDF. I do not believe it has received an across the board rise since for a number of years (i.e., before the Labour party got into power). The higher salaries commission should be tasked with determining that.
Air Combat Force
I have never seen the Air Combat Force as a requirement to defeat an invasion. Simply put the logistics in trying to mount an invasion on NZ, make it near but not impossible to achieve. However, that does not mean that NZ is not immune from military threats to its sovereignty and a viable Air Combat Force is a critical deterrent IMHO to that. It does not necessarily have to be a 40 strong force that mixed advanced trainers and A4K, though you could argue if the purpose is to deter aircraft carriers, then such a force is justified. From a purely NZ perspective a twin engine fast jet is required (ability to recover on one engine and range been the deciding factors) focused on maritime strike, air defence and strategic strikes on say naval bases, airfields etc. (if you intend to operate overseas). The numbers depend on whether governments seen them as a contributor to international operations. If a sustained but limited overseas deployment capability is required by government then a minimum of three to four operational flights of 4-6 aircraft would be required. I would emphasize quality over quantity in this area.
While I have some sympathy for an Attack Helicopter Squadron to support 1 Brigade, I seem to recall that Afghanistan experience showed that fast jets could arrive on site sooner, remain on station longer and carry more stores. Something like the FA-50 might be more appropriate from an NZ perspective say in Australia, but operations into the Pacific lean more to a rotary attack capability (short of purchasing an aircraft carrier or F35B)
That said I do agree the first emphasis right now should be on sorting out the shortfalls in current capability. I tend to agree with most suggestions around additional helicopters, P8A with standoff weapons, improved tactical / strategic lift etc. The one area I have concerns with is the integration of large UAV into New Zealand air space and civilian traffic control systems. I don't have the necessary knowledge in this area to come to a conclusion.
Navy
I concur with the general view that 3 frigates are required, but I am open to the Type 31 as I am the Type 26 or another class, but realistically I suspect keeping it in the 5Y family might prevail. In terms of other capabilities, I would lean towards a further 9 Blue water ships (assuming the personnel issues above are addressed). I would replace Manawanui and the IPV with a single class of a multi role vessel of around 1,800 Tonnes - UAV capability only, dynamic positioning and modular diving capability. (Lt Cdr level command). I would replace Canterbury, the OPV and the proposed logistics ships with 4 Damen Cross type Vessels, however NZ would need to decide on the size of the rotary wing given the limitations on the Damen Crossover (so the Fassmer design might work). That leaves the POLAR OPV and the AOR. Any inshore capability should be a secondary consideration taking into account Whole of Government as well as potential defence usage.
My aim is to consolidate the number of classes, systems etc. operated by the navy. So a common Combat Management System for the Frigates and Damen vessels, ExLS say for the frigate and Damen for Local / Point Air Defence as examples.