Of course it is easier to run a smaller airport. I like Auckland and Sydney (yes, that is still small!). The lesson to be learned from the Antipodes is security. These airports do security properly, yet it does not cause undue delay.
However, I hate to say it, but still the one to beat is Chiangi, without a shadow of a doubt. Since I have been using it, it has expanded from one, to two, to three and shortly four terminals (including the loco). Outside the airport, the transport infrastructure has been steadily upgraded and copes well with the 40 million or so passengers it handles a year. Still it has an overall relaxed atmosphere and works remarkably well. My only gripe is their attitude to security screening, which although quite quick, sometimes borders on the anal - such as screening certain inbound flights.
I also hate to say my "home" airport of BKK remains a problem child. They will continue to improve things in true Thai fashion, but will struggle with the sprawling nature of the place and materials used for ever. It's just a bad design.