In Sopoaga, the All Blacks felt they had someone they could rely on; someone who had banked enough experience in his 16 tests over three years and seven Super Rugby campaigns to handle pressure, whether that be kicking big goals like those he did on test debut at Ellis Park, or taking the right option with ball in hand. Super Rugby is a great breeding ground but test rugby will always be a different beast, one where time and space is squeezed and rush defences are now in vogue. Learning to remain calm and adjust to these pressures happens in the moment.
With the added scrutiny and expectation that comes around the black jersey, few stroll into the test arena and immediately make it their own. And for a hugely influential position such as first-five, experience is an extremely valuable commodity.
As it stands, outside Barrett, the All Blacks do not yet have a first-five with those credentials.
Take Barrett. His first four seasons with the All Blacks were spent coming off the bench for cameos at fullback. Only after Dan Carter left following the 2015 World Cup was he given the chance to seize his opportunity, pushing past Aaron Cruden and evolving into the player he is today.
Time in the test saddle is imperative.
At 26, even Barrett is still learning his craft.
It has been similar with McKenzie. The All Blacks always believed his best role was No10 but he has now effectively had two seasons at fullback.
Partly that is due to circumstance, with Ben Smith taking his sabbatical. But with such limited elite level experience at first-five, McKenzie must now prove with the Chiefs this season he has the required temperament and game-management to match his brilliant attacking skills.
That is no given.
First-five, more so than any other role, needs someone capable of summing up the myriad options and contrasting pictures in an instant. Whether McKenzie is that guy remains to be seen. There is not yet enough evidence to argue either way.
This brings us to Mo'unga, fast shaping as the big beneficiary of Sopoaga's imminent exit.
By the end of last year he was, for many, New Zealand's second-best No10. During the Crusaders' run to the title his growing confidence was evident in the way he regularly challenged the line, an asset that forces defenders to hold and, thus, creates space wider out.
"After last year you learn so much about yourself as a rugby player and a person," Mo'unga, born in Christchurch to a Tongan father and Samoan mother, told the Weekend Herald on the end of year tour after performing strongly against the All Blacks for the Barbarians before coming off the bench in the mid-week match in Lyon.
"I feel like I'm right in the mix. Steve [Hansen] wouldn't have put me in here if I wasn't. I've taken great confidence just coming in and training, having turns at running the cutter. I'll do what I can and if the opportunity comes I'll try nail that. There's three 10s here so to be the fourth one I've just got to keep challenging them."
Already, that dynamic has changed. Three tests in June against France, a typically poor touring team these days, now shapes as a chance to fast-track Mo'unga's progress alongside McKenzie and Barrett.
While McKenzie sits ahead in the test rugby experience stakes, after two full Super Rugby seasons at No10, Mo'unga's case is likely to only get more compelling, especially with the All Blacks likely to utilise Jordie Barrett's utility value.
The All Blacks will, of course, be disappointed, frustrated even, to lose Sopoaga. But they never panic over things they can't control.
They could look to their Sanzaar counterparts and see the Wallabies with Bernard Foley and a big drop to Reece Hodge or Kurtley Beale. South Africa have persisted with the flighty Elton Jantjies, when the better option is Handre Pollard. Few test nations have two, let alone three, quality options at No10.
Outside the established contenders here it could also be a big year for Taranaki and Blues playmaker Stephen Perofeta. He possesses brilliant feet, and showed in his first start against the British and Irish Lions some of his vision. Still he is only 20 and, with the Blues, expectations must be tempered.
This year the scene was always set for a scrap to sort the All Blacks' first-five pecking order. Sopoaga's decision to leave in his pomp strips away one key component and heightens intrigue around others.
