So he should be. Opening the innings, with its built-in potential to construct a long stay at the crease should lead to higher figures. Batting down the order brings different circumstances to bear; he has often had to do a rescue job.
However, McCullum is yet to win the confidence of the cricketing public as an opener. When things go wrong, as they very messily did in the first test, he is often a scapegoat for criticism that Twenty20 has ruined our approach to test cricket - criticism which is entirely justified but which does not reside exclusively in the psyche of Brendon McCullum.
The Black Caps have talked at length about the need to bat time - but then often employ a batting strategy which, if it doesn't come off, simply gives the opposition more time to grind out a victory.
When McCullum, given rein to play his more free-wheeling style, gets out, the opposition figure they have removed their most dangerous opponent.
Their mental strength grows while New Zealand's seems to curl in the foetal position.
There is only one answer: change the way they are playing as they are doing in Hobart.
Go back to the time-honoured test traditions of defending one's wicket, playing time, not crowd-pleasing shots. Test cricket is a game of chess, not pinball.
Many of the great top order batsmen profited from reining in their talent and expressing themselves through a stubborn defence and two or three run-gathering strokes only; selling their wicket as if it had an umbilical cord attached.
New Zealand top order batsmen, including McCullum, have not embraced this quality much.
It can be argued that true greatness is an opener who can stay and score freely. Maybe so - but McCullum isn't really achieving that either, at least not when compared to someone like the Indian dasher Virender Sehwag.
He has played 92 tests, McCullum 59. Sehwag has 22 test centuries and 30 half centuries or better. McCullum has six and 19. Sehwag has the astonishing test strike rate of 82.12; McCullum 62.15.
So why not change the strategy and technique - even if McCullum is now 30 and approaching old dogs and new tricks territory?