I'm very left wing so obviously my opinion is very biased in that direction, but I think Key gets a great deal of pump up from the political commentary classes because he did the politicking part of running a government successfully. He was able to keep the National party on message, was able to fudge away a bunch of different controversies without getting tarred by them and is still probably the most popular National leader of the last 20+ years.

However, if we look back at what Key's government actually did its pretty clear to me that the outcomes of their policies are bad, are being felt now and will be felt for a long time to come.

As one example, tax cut obsession, plus austerity during and after the GFC downturn has seen a huge degradation and under-investment in infrastructure. The only reason they "balanced" budgets is by not putting money in where it was needed. That's why Dunedin, Nelson, Hawke's Bay etc are so desperate for new hospitals and why they are so expensive now.

Its a bit of a blunt exaggeration but the infrastructure you build today is almost always going to be cheaper than what you build tomorrow. And then the infrastructure they did build, such as Transmission Gully, was done as a PPP, which in the long run basically always costs more than doing it ourselves. Massive over-investment in roading and under-investment in rail & coastal shipping also locked in (and now Simeon is doubling down) transport emissions for decades.