I don't think you need to cut the players in a team down from 17 - I think you could get the same result by cutting First Grade Squads.
Currently First Grade Squads consist of about 25 players. Cut this down to 22 and you free up 48 players. Clubs pay less $$$ more players for more teams. If a Club cops injuries they go to their Toyota Cup sides and blood youngsters
The problem with cutting the NRL squad without a corresponding cut in the fresh inter-change bench, is that it exposes teams to massive problems if they have injuries - 21 is not enough in a 17-man game. I also think the 17-man game is contributing to the rate of injuries.
Maybe Warren Ryan's 11-a-side model makes just as much sense financially as it does in regard to opening up the game.