John Key is a very loved an honorable man. His leadership for the rebuilding of Christchurch after the earthquake that destroyed nearly the whole of the downtown has been outstanding.
I had the pleasure of flying him and his wife to Antarctica one year as the New Zealand aircraft could not go due to the ice runways not being available so he flew down in my ski-equipped C-130. Great conversation for several hours.
Having been going to New Zealand for over 20 years and followed him through his entire 10 years in his party and his tenure as PM I have zero reason to suspect anything nefarious in his stepping down. I think he simply wants to go out on to, which he is, and cost nothing in the process as the timing means no special elections thus cost to the country.
Glad to hear it. Wish the same could be said for American and Israeli politicians, as a whole.