That will likely bring in a big leisure crowd. Any business to be had? You'd think that there would need to be some to make a good case for both AA and UA to make the jump across the Pacific, even with 787s. A larger leisure crowd might mean more premium availability to be had, although that doesn't mean they will be readily redeemable - either at AAnytime level or reserved for upgrades.
My guess on that is because there's a lot more lushness to be found in NZ which is readily accessible from many major cities or towns in NZ compared to Australia. Lovely lake region around Taupo, hot boiling mud at Rotorua, laid back capital of Wellington (still more classy and chill compared to Canberra), rolling hills and wine at Hawke's Bay, skiing or sports in Queenstown...... to get the same thing in Australia means going here there and everywhere; not cheap.
On top of that, your USD probably goes a lot further in New Zealand than in Australia (especially in Auckland vs Sydney).