Looking at the world cups, what is needed to win it more than anything else, is a really powerful all-round pack, and a really good half and first five combination.
In 1987, the AB's did it with a great pack and Kirk-Fox. Fox was utterly brilliant, ran the game with precision. Kirk I rate as one of NZ's most underrated players. He is second to me behind Loveridge in recent times. He was a Rhodes Scholar, say no more!
In 1991, the Wallabies had the best pack I think they have produced in my time, excellent across the board. They had what I consider the best half-back-first five combo I have seen (I didn't see Edwards-John in the flesh, they may have been better). They were streets ahead of any combo at that point.
In 1995, the South Africans had a great pack that could match the AB's (at least food poisoned), one of the best half backs of their history Joost Van der Westhuizen who is underrated by Kiwi's but was a devastating player. Joel Stransky was not utterly brilliant but with Joost, was a great combination.
1n 1999, the Australians again had a really good pack, and another utterly dynamic and brilliant half-first five combo, Gregan and Larkam. What a team!
In 2003 it was the turn of the English with the then at his absolute best Johnny Wilkinson and Matt Dawson, another underrated halfback. The pack was tremendous in every way.
In 2007 the South Africans had a great pack, especially at lineout time. Their half back Fourie Du Preez is brilliant, along with Pichot the best in the world. And we saw the coming of age of the erratic Butch James, another underrated player.
So it seems to me that to win the world cup, above all you need these elements. It helps to have flashy backs and you must have great defensive backs. But if you want to control games, you have to have a really good all round pack without weaknesses and a half and first five that can control the games. There must be a world beater in the halves somewhere. Like a Fox, Farr-Jones, Lynagh, Van der Westhuizen, Gregan, Lynagh, Wilkinson, Du Preez.
So NZ, if you want to win the world cup, you need to get the forwards to a point of completeness. No more lineout weaknesses, keep the scrum strong, and with powerful mobile loosies. You need to find a half back; at the end of the day Bachop, Marshall and Kelleher were not there. They were very good but not great. And you need Carter at his best. He is certainly there, but he has to be there when it counts.