It is a typical story of long haul (ULH in this instance). Solution to land at Philly, EWR etc would suit most of the passengers on this particular flight better but the implications to the whole network will be there for a good 7 if not 14 days, with a good probability of making literally thousands of passengers unhappy. There is a general rule to try to isolate the problem where it is and carry on. One missed round trip (with airplane and crew in position) is way much better than a cascade of delays and cancellations. Same applies to rebookings - no ticketed pax will be denied boarding in AKL next day just because you have a full load of pax from yesterday's return awaiting their flight.