I always find it somewhat curious when experienced travelers blame an airline for ticketing a risky connection - like you didn't realize the risk of a 45 minute connection when you booked the flights?

I don't really see UA "fault" here that would justify opening saver award space. It was the NZ delay that caused the misconnect - that's not UA's fault. You could try to talk an agent into booking the extra segment for you. Maybe it will work.