So I've decided to do it myself, in order to see if there actually is a clear difference, man-for-man.
I've tried to line up the players by role. Both teams have players that do similar roles generally, with only a couple of exceptions.
I'm looking at their world cup so far, as well as their numbers since 1 Jan 2013 in New Zealand and Australia.
Role 1 - Slower opener
|2 year Average||43.00||37.00|
|2 year S/R||85.08||87.13|
Guptill is in better form, but the 2 year numbers are very close. These are two players of similar ability who are both playing good cricket. Both tend to be slow to start, but are capable of increasing their scoring rate once established.
Role 2 - Fast opener
|2 year Average||38.00||40.75|
|2 year S/R||135.02||104.21|
Again the numbers are very close. Warner has the higher average, but McCullum scores faster. Both are remarkably good at both scoring boundaries and finding singles, but both are prone to hitting bad balls straight to fielders. McCullum has shown a weakness against left-arm spin, so there's a chance that Clarke might bring himself on to bowl early on.
Role 3 - First drop
|2 year Average||51.08||60.92|
|2 year S/R||85.64||94.77|
These two players are the best batsman for their team in recent times. Smith is ahead on these numbers, but it's wrong to say that Williamson is a weakness in the New Zealand side. Both manage to score at a good rate without looking like they're trying. Both also have a big impact on their team's chances of succeeding. New Zealand win 45% of the time when Williamson scores under 40 and 62% when he scores 40+. Australia have won 53% of the time when Smith's scored under 40 and 86% when he's scored 40+.
Role 4 - Innings builder
|2 year Average||46.82||23.66|
|2 year S/R||79.30||80.49|
Clarke's had a slightly better world cup, but Taylor has produced more quality innings' over the past 2 years, averaging almost twice what Clarke has. These two are both great players, who often play roles that allow others to shine. As a result, their numbers don't truly tell the story of their contributions. Both players' numbers are also a reflection of their battle with injuries.
Role 5 - rebuild or launch
|2 year Average||44.76||36.82|
|2 year S/R||94.63||94.70|
A really interesting role in modern cricket is the number 5 batsman. Their role is sometimes to steady a rocking ship, and other times it's their role to attack, and build on the foundation of the players above them. It is difficult to separate the ability of Watson and Elliott to do this role.
They also both have a role to play with the ball as the extra bowler:
|2 year Average||25.88||101.50|
|2 year E/R||6.56||6.37|
Elliott has been more expensive, but has also broken partnerships quite regularly.
Overall, it's really difficult to separate these two with bat and ball. I'd probably back Elliott as a batsman, but Watson with the ball, despite his numbers not being as good.
Role 6 - Agressive batsman
|2 year Average||41.77||33.42|
|2 year S/R||125.96||125.13|
One of the dangers of comparing players like Anderson and Maxwell based on statistics is that they are often asked to do different jobs. Against South Africa, Anderson's job was not to come in and score at a massive strike rate. His job was to play sensibly and carry the innings through. Over a longer term it's difficult to separate Anderson and Maxwell. Both are capable of being absolutely breathtaking with the bat.
Both play quite different roles with the ball, so I'll look at them later.
Role 7 - Wicket-keeper batsman.
|2 year Average||38.88||41.11|
|2 year S/R||128.84||111.11|
Haddin has had a much better world cup, but it would not be difficult to argue that Ronchi has been the most effective death batsman in the world in the past couple of years.
They're also difficult to separate with the gloves. Both are solid keepers who have made a couple of key mistakes, but in general, they've done the job required of them sufficiently.
Role 8 - Bowler who bats
|2 year Average||15.66||44.25|
|2 year S/R||123.68||114.56|
Faulkner and Vettori have very different styles, but can both be very effective. Vettori has rediscovered his batting form of 2008-2012 in this world cup, during which time he was one of New Zealand's best batsmen as well as being an outstanding bowler. Contrastingly, Faulkner hasn't found his rhythm since returning from injury.
Role 9 - Right arm opening bowler
|2 year Average||28.97||20.44|
|2 year E/R||5.53||4.37|
Hazlewood has the advantage here numerically, but some of that is due to Southee having a role bowling at the death. I don't think many selectors would pick Hazlewood over Southee, regardless of the difference in their stats.
Role 10 - left arm opening bowlers
|2 year Average||22.09||14.37|
|2 year E/R||4.58||4.34|
Starc and Boult probably been the two best bowlers in the tournament. They both offer different things. Starc bowls into the pitch with a high arm action that causes the ball to bounce higher, but it also gets less movement and arrives to the batsman later, despite the quicker speed through the air. Boult bowls over his front foot and tends to bowl more deliveries along the wicket than into the wicket. As a result, the ball swings more and arrives at the batsman faster. (Ed Cowan, after facing both, commented that Starc might bowl 5-10km/h faster but you have a lot more time to face the ball. Boult certainly feels faster.)
It's difficult to separate them, but not impossible. Starc has been the premier white ball bowler in the world recently.
Role 11 - 3rd seamer
|2 year Average||19.00||25.15|
|2 year E/R||4.26||5.04|
Henry has only bowled 8 overs this world cup, as he wasn't even in New Zealand's original squad. His first 5 overs included 2 maidens and conceded only 9 runs against South Africa. He went the distance in his next 3 overs, but even then, a large proportion of his runs came through edges and mis-hits. Johnson is a master with the red ball, but hasn't had the success recently with the white ball that he had earlier in his career. It's still difficult to complain about an average of 25 and taking a wicket every 5 overs.
Role 12 - 4th seamer
|2 year Average||22.69||26.57|
|2 year E/R||6.42||5.45|
This is a slightly more difficult comparison, as Anderson generally bowls at the death. His economy rate here is outstanding, and he's taken a lot of wickets. However, taking wickets with bad balls isn't necessarily a trait that is repeatable. Faulkner looks like a better bowler, despite his numbers not being quite as dramatic as Anderson's.
Role 13 - Spinner
|2 year Average||35.12||32.91|
|2 year E/R||4.10||5.24|
Vettori is in a different class here. It's probably the only place where there's a clear difference in quality between players doing similar roles in the two teams.
Overall it's really difficult to separate the two teams. Both have a team full of good players in good form. They have players doing similar jobs, often in similar ways.
I don't think I can honestly say at this point which team has better players. The more you look at this match, the more mouth-watering it becomes.