I can see AKL-ZQN, IVC and DUN (and maybe CHC) as being the only flights that could support extra time for service. Factoring in that we'll have a lot more main trunk A321 flights when the domestic A321neo fleet straights arriving I don't see a lot of opportunity to significantly change the offering or offer paid snacks.

I do agree with changing things up a bit, they used to offer the mini OSM bars as part of the breakfast service, so there are certainly opportunities there to do things slightly differently and offer other alternatives.

Air NZ obviously see mandarins as something easy to give out, but they then have to deal with the peel and contamination of surfaces such as tray table because it is quite sticky.