Stumpy,
You may well be right when you say that Rotorua won't work, I tend to agree, BUT I think it has a much better chance of working than Hamilton will for either Air NZ or PacBlue.
Rotorua is different because it is a destination in it's own right, Hamilton was only ever a gateway to other places, one of these places being Rotorua.
I'm not sure what you mean by AirNZ making a mess of themselves when they left NZHN. They were painted as the bad boys by the local media. However some local media has never been known for letting the facts get in the way of their version of events.
Even still they beat up any Air New Zealand action, a headline recently loudly procalimed that Air New Zealand had slashed flights to and from Hamilton. This statement was made to look as if Air NZ was deliberately picking on NZHN when in fact they have cut schedules to many destinations.
HIAL have to take some responsibility for the passenger drop off in NZHN with the cost of car parking. I think they might have addressed that issue recently but not before people had decided that they could travel by road to Auckland for less than they could park at NZHN.
There's been hints of incentives for Air NZ to go to NZRO, I have to wonder what incentives PacBlue got for going to NZHN.