Warriors definitely need to be included sooner rather than later. Strategically it is important for the game to grow its presence in New Zealand as much as possible and unlike a lot of other markets, you could easily create a competitive team from Auckland without taking players from any of this year's teams.
It wouldn't be the worse idea in the world for the NRL to consider going to an odd-number of teams to accomodate them either. Whilst fans don't like them because it means their team isn't playing, there are benefits to them from a player welfare and giving the perception of a competitive competition.
If they want to expand in twos, I'd say Melbourne and Redcliffe should be the only franchises in contention. Adding another Sydney club doesn't help grow the competition from a reach perspective and arguably draws upon the same systems which are already supporting the Tigers, Eels, Roosters, Dragons and Sharks.
Redcliffe at least has the Sunshine Coast it can tap into to help under pin its side, Melbourne helps the NRLW become more National and maybe we can steal some players from the Rebel's Super W side.