New Zealand's problems start at the top
A good rebuilding job can only be done if it starts with the foundation, which is the lesson New Zealand should take with them as their Test side leaves South Africa. Their all-round woefulness in the series is a symptom of the trouble at the top and the opening combination should be the first to be examined.
By New Zealand's own admission, the current pair is not what they planned on. On the eve of the series, Martin Guptill was due to open with Peter Fulton, who was then ruled out because of a recurrence of a knee injury. Fulton did not have a great record either but he had been recalled and not having him forced changes to the plan. Brendon McCullum to promoted himself to open, and in so doing he had to fundamentally change his own approach.
McCullum is an aggressive player and wanted to infuse that belligerence into his troops. He arrived in South Africa and talked about playing positively, not asking his team to cower to the notion that they were underdogs. That did not work in the tour opener - the first Twenty20 - when New Zealand's enthusiasm to show intent had the same result as a kettle that is boiling over.
McCullum acknowledged New Zealand had showed no sense of judgement and they returned with a better idea of how to apply the attacking mindset in the following match. The same can be said of their efforts in both Tests.
New Zealand's first innings in Cape Town and Port Elizabeth were implosions caused by poor shot selection and being overawed by pace, but they staged competent comebacks in the second innings. At this level, that is just not good enough. Matches don't start in the second dig and McCullum was one of the first to say so.
He made attempts to lead by example, reining in his own game so severely that those who have covered his career since its beginnings say this is the most restrained they have ever seen him bat. They were correct because in this Test match McCullum was at his most reserved. His innings in this match are the slowest and second slowest of his career in terms of strike rate. The 13 in the first innings took 97 minutes and 61 balls while his 11 in the second took 88 minutes and 57 deliveries.
Like a Test opener should, McCullum saw off the fast bowlers and the new ball. Like a Test opener should not, he went on to be dismissed by the spinner three times in four innings this series. McCullum had called Robin Peterson "innocuous," perhaps in his attempt to disguise his own issues against left-arm spin. In six of his last eight innings, he has been dismissed by a left-arm spinner. They have also accounted for his wicket almost a quarter (22%) of the time even though those bowlers have only bowled a sixth of the overs (17%) to him.
As the new Kevin Pietersen, in terms of that particular weakness, McCullum will have to make some technical adjustments to his game such as being able to pick the straight one, but the wider concern is that he is actually better suited to the middle order. Even though he averages slightly higher as an opener, 35.77 compared to 35.12, those numbers are inflated by the double-century against India. Moreover, New Zealand would want their two best batsmen, when Ross Taylor is back, in the No.3 and 4 positions, similar to what South Africa have in Hashim Amla and Jacques Kallis. And if Jesse Ryder returns, that middle order will be stronger.
McCullum's style of play seemed suited to opening when he first moved there in that India series in 2010. On the evidence of recent performances, he may be better suited to the middle order, which will leave New Zealand still searching for an opener.
Martin Guptill's 48 should not be considered a redemption and although it will be used as a reason to keep him in the XI, they should still cast the net wider as they search for other options. Guptill has only scored a half-century once in his last ten Test innings and his problem of nicking off has not been solved. He also struggles against swing, which leaves him fending balls awkwardly and getting edges.
Even in this innings, he started by taking his eyes off a Dale Steyn bouncer and nearly gloved it to the wicketkeeper. Guptill's drive is still impeccable and he grew in confidence as the innings wore on. The ball that dismissed him was a seaming delivery that came back in to him and it would be unfair to judge him on that alone.
Overall though, Guptill has not done his job. Kane Williamson has had 18 innings at No. 3 in Test cricket and only five times has he been able to walk to the crease with the score over 40. Acting as an opener has restricted Williamson's development as the anchor of the batting line-up, which is how New Zealand see him. Arguably New Zealand's most talented young batsman, Williamson should be better nurtured and Guptill's poor form isn't helping with that.
So where do New Zealand turn? The answer may actually lie lower down where BJ Watling has showed guts and guile. A bonus is that he is an opening batsman who has played the role in Tests before. When he made his debut against Pakistan, Watling was picked as top-two player. Now, he is the designated wicketkeeper and so he may have to give up that responsibility to face the new ball.
In New Zealand's current situation, having Watling open the batting would not be the worst call. In all three innings in which he has shown fight on this tour, Watling has been strong with the cut and drive. Today, he also showed astute decision-making skills in taking risks, especially against the best bowler of the day, Dale Steyn, who Watling did not hit for a single boundary.
He also did a fine job ushering the tail through the latter parts of the first innings. Watling allowed Trent Boult time to settle in and then trusted him to hold his own as the two put on the highest partnership of the innings.
Of the current line-up, Watling seems to have the most secure and fearless mindset and he has combined control with class. All those sounds like the qualities of an opening batmen, don't they? If only New Zealand had two of him.
Firdose Moonda is ESPNcricinfo's South Africa correspondent