I'm still tossing around variations of this idea:
Start the year with a revamped NRC with all the test players available. At the same time, NZ play their Mitre 10 Cup with all their test players available. Re-live their NPC glory days.
Then from the NRC, Australia picks 3 "state of origin" rep teams:
NSW
Qld
Best of Rest/All-sates/Barbarians
Likewise, NZ picks their 5 regional super teams:
Crusaders
Highlanders
Hurricanes
Blues
Cheifs
Our 3 join their 5 for an 8 team Trans-Tasman comp: simply play every other team once for a first past the post winner. This is promoted as a "state of origin" type series in Oz, and recaptures something of the best vs the best from the original S12 concept. It's short and sweet and leaves fans wanting more of its intensity. And that's the way it stays. And that's why it drives up revenue.
From there, the Wallabies and AB's are chosen for the test season: in-bounds, Bledisloe, TRC, Europe.
So the year builds to a crescendo. NZ and Oz work together. There's domestic competition satisfaction for both countries. A 'super' TT comp to raise revenue. And players move through a funnel towards the test team.
As an added bonus for the Sydney clubs, there's no NRC at the back end of their season. So they can have a national club comp or do whatever they want. Could also add value to an overall package for broadcasters.