The move to nighttime RNP approaches at Queenstown is a sensible development.
RNP by day has proved its worth over a number of years and I know of no reason why it shouldn't be just as successful once the sun goes down.
The airport will require considerable upgrading before night ops can start, and some of these improvements (runway widening for example) can only make daytime ops even safer.
There will still be occasions when aircraft can't get in because of weather. The problem usually is not the cloud base but turbulence preventing stabilised approaches. There was such a day last week when I think there were more missed approaches and diversions than landings.