Really hard to regulate or control the present T P A format
It is not hard to 1. level the playing field 2. fix TPA distortions 3. fix the brown paper bags AND 4. bring the game back to respectability and profitability - if the NRL is brave enough to think outside the box:
1. NRL (not the clubs) contracts the players - The NRL gets the TV rights money after all
2. Players specify the length of contract they seek
3. Players are auctioned. Clubs blind bid a percentage of their salary cap for their top players. eg 4.6% for player X.
4. The top (say) 10 highest percentage winning bids are done deals. Clubs then adjust their bids for the remaining players, with the top 10 winning bids again succeeding. Bidding rounds continue until all salary caps are exhausted.
5. Impact on the total salary cap of successful bids are objectively adjusted for loyalty (existing player), years of service, juniors, etc. eg a 5% bid for a player might only cost 4.5% of the cap to allow for these objective factors. Current minimum wages, etc can continue.
6. Players are free to earn ANY amount of income from any (legal) source, because only the bid percentage is controlled.
Some other benefits:
1. The NRL can pay extras for potential code hopping stars without adversely affecting equity between clubs
2. Bidding is a free market, so the system doesn't encourage unfair manipulation by the NRL or the clubs
3. The NRL is empowered to manage the profitability and financial security of the game, as well as the amount being invested in the grassroots