Students of politics can derive much innocent enjoyment, if they have a mind to, by registering changes in how the leading figures are deployed and speculating as to what it tells us about their ratings. Even Key himself would not have been immune from such voter reactions.
He was, of course, an expert performer. But, even then, viewers can have too much of a good thing. I can only speculate, but I am as sure as I can be that the National Party's polling will have told it, some time ago, that a significant sector of the public was getting tired of seeing Key take the limelight on every issue.
The outcome is that other ministers were then seen more often. And they, too, would be constantly assessed. I can make, I think, some intelligent guesses as to how they rate.
The polls will show that women are often seen as less hard-nosed and confrontational and, therefore, more acceptable.
Despite their policy difficulties on occasion, a Hekia Parata or an Anne Tolley or a Paula Bennett will pop up frequently. Even Judith Collins trying, perhaps too late, to soften her image, will have hoped for brownie points by virtue of her femininity.
Of the men, perhaps the most interesting case is that of Steven Joyce. There was a time when the Minister for Almost Everything was constantly on our screens and airwaves. But he has been through a fallow time recently, when he has been seen and heard less often.
His reduced exposure is not entirely his own fault. He was so often wheeled in to deal with crises such as the Novopay debacle that he became associated with bad news. And he wasn't helped by often implying, somewhat dismissively, that difficult questions were the questioner's problem rather than anything to do with him.
It is a fair bet that the experts will be anxiously analysing how he rates in his new job as Minister of Finance. Even more crucially for the new government, what is the reaction to Bill English as Prime Minister? National Party fingers will be crossed on that issue.
It is always worth remembering that politics is a contest, not just between political parties, but between individual politicians as well. A poor poll rating can mean bad news for the career prospects of ambitious politicians.
Bryan Gould is a former British MP and Waikato University vice-chancellor.