Now I get it a little more what you were getting at LoudStrat.
A problem then would be all these one-off teams such as the Aboriginal side and Maoris - when they play one-offs they are interesting to people, but when they play in a competition, no one seems to care and the comp is devalued.
The best way to increase the appeal of the international comp is to fix the elligibility rules. I find it very stupid to see Moi Moi wearing a NZ jersey, and packing in with the Tongans in Rotorua for prayer before this years' 4 Nations. It's also idiocy to have Jarryd Hayne rot on the wing and have a completely bleak 4N when Aus have a lot of good actual wingers to call on. This being the same Jarryd Hayne that last year was a Fijian for the WC.
I realise why it happens - it's extra money for the players involved in 4N then if they played the Pacific Cup, but it ruins the whole credibility of an international game. The appeal of the internationals is that the players when they're born are bound to a jersey, as are the supporters (if you're Australian you support the Roos, if you're Serbian you support Serbia even if they get flogged)...
Fixing elligibility would do more for the strength of RL internationals than any new comp.