I definitely think the new .NZ extension is a great opportunity for hobby domainers. The average sale value is low enough that major players will stay out, but high enough to see some good ROI for reg fee domains.
In the days leading up to the public registration I did some research into the industry over there. I couldn't see any 5 figure sales, but 4 figure sales are possible. My perception is that .NZ is going to overtake the current #1 extension .CO.NZ, so previous sales figures should be a good indicator.
There are plenty of chances to turn a $20 reg fee into $200 if you pick the right domain and find the right buyer. It's certainly exciting seeing the quality of name you can pick up for reg fee, but having experience in the .AU space has helped me learn to filter. What sells internationally does not sell locally so you have to be very careful.