Airports in NZ are not more dangerous than Australian airports, are they?
Have you seen the state of the ramp at Auckland recently. You would be asking for trouble letting pax loose. I'm amazed there haven't been any serious incidents on the regional gates.
Had a good example the other day of tranship bag delays caused by A320s operating as replacement on the domestic network. I'm sure if a few things were tweaked in the right direction you could make it work though.