Ditto all this talk or reusing the ANZAC upgrades /systems on their replacements. Much of this may be obsolete by the time we make the switch. The naval gun and the Phalanxs come to mind.
The naval gun I am not so concerned about. The 5"/127mm naval gun has been used by the USN (and others) for generations. I do not see that changing any time soon, especially with some rather interesting rounds available from Italy.
I do think it might be worth having some updates/refurbishment done (change from Mod 2 to Mod 4, lengthen the barrel, etc.) but overall I suspect the bulk of the system could and should be re-used. The Phalanx... could still have some use, but I would rather the RNZN start migrating to the 35mm Millennium Gun, which has a similar role but I believe is more effective at this point.
I do like the notion of the RNZN (and the RAN, and a few other navies) adopting some sort of modular or containerized system for at least part of the potential weapons loadout. Having something like this in place could allow a greater degree of customization of a vessel for a particular deployment or area of operations. At the same time, it can free up weapon systems for when a vessel is undergoing a major refit or repair work, which makes a particular vessel unavailable for prolonged periods.
I have some reservations about the LCS module system, partially due to how far behind they seem to be, and at what cost... but also because the USN had been planning on the LCS being 'forward deployed' but supported by other USN assets like the AB DDG's. A modular weapons system which might be appropriate for a corvette, IMO would hardly be appropriate for a blue water frigate or destroyer which could be operating on its own, or as the lead ship of a taskforce.