Business Premier really killed off first class for Air New Zealand. Air New Zealand had a horribly dated product when they announced business premier. Their first class seats were not flat and just outdated recliners and their business class was 50'' pitch. The business premier seat in my opinion is actually better than the first class seat was.
I flew the NZ
first class shortly before it was removed in 2003. Service was spectacular, but the product wasn't. Compared to what first class was, the recliners with only two functions (recline and leg rest) were wide, but not that great for sleeping compared to the suites on other airlines.
Finally the price was quite high for the seats. New Zealand is not a wealthy country or a vacation destination for the enough of the rich and famous to warrant first class. The market for business travel to New Zealand is slim compared to Australia. Not many airlines even offer First Class to New Zealand. Two class makes sense for the market.
If you have never designed an airplane part before, let the real designers do the work!