Given that there's plans to keep introducing more teams, junior production seems like it's going to become an even bigger area that teams need to be good at to maintain success.
In all honesty I think the only way to maintain a strong balanced comp is to encourage teams to invest more. If you allowed teams to have a financial incentive to ensure they're scouting and producing the best quality possible.
I think it'd entice most teams to invest heavily in junior production if the NRL allowed a percentage of player payment to be excluded for every season spent contracted as a junior.
If someone had been with the club since their schoolboy days, you could get maybe 2% of their pay excluded for each year up to a maximum of 10%. So if you have a gun half that's been plugging away getting better since school, they debut and kill it and somehow get an origin call up in their first season. The Rabbitohs come chasing with a million dollar offer. So we can match it with 10% outside the cap (900k on the books 100k legally excluded). But assuming the kid was worth it we might opt to do a mill on the books and add the excluded part on top to rule out the possibility of losing the next JT. If you had 10 or more good players with 10% exclusions (say they average out at $500,000/player). It adds up to $500,000 you can throw at a player in a position you need.
With that kind of incentive, it'd mean every team would have to either improve their production line or risk being left behind.