But these things can't be rushed and history is a true guide on this. Remember 1998 and how the All Blacks couldn't find anyone to replace Frank Bunce at centre?
They didn't manage it in 1999 either and after the brilliance of Walter Little and Bunce, the All Blacks didn't have a regular or effective midfield combination again until Aaron Mauger and Tana Umaga came along in 2003.
It was all too brief and if there was a glaring deficiency in the 2007 World Cup campaign it was that once again, the All Blacks arrived without an established midfield pairing.
There were plenty of reasons why they recovered to win in 2011 and retain their title four years later, but somewhere near the top would be the contribution of Ma'a Nonu and Conrad Smith. Those two became not only the most experienced partnership in history, but arguably the best.
But it took them a while to gel, really gel that is, when they became the first choice selections in 2008.
When they signed off in the World Cup final last year, it was their 62nd test together. To imagine that the All Blacks could replicate quickly and easily what they had with those two is unrealistic.
Crotty and Fekitoa don't have the same individual experience as Nonu and Smith had when they were thrown together.
Crotty made his debut in 2013 but has been in and out of the squad until this year.
Fekitoa arrived in 2014 and started this season with 14 caps.
They are both still trying to establish their credentials in their respective positions, while trying to form an intuitive understanding of one another.
Their performances to date can't be fairly judged against those produced by Nonu and Smith last year.
It has to be remembered that these are early days for Crotty and Fekitoa and the important thing is to build a solid defensive screen together.
They can tick that box. Crotty defends above his weight and Fekitoa covered the space supremely well in Christchurch and made a number of big tackles.
That defensive unity will be the foundation for everything. If they get that right, then it's probable the rest of their work will follow a similarly unified front. Their handling will improve, their timing will click and Fekitoa in particular will become a line-breaking asset.