The question is relatively straight forward. Over the past several years, we've seen players arguably ready for the rigors of the pro game get sent back to Juniors at age 19 when they had nothing left to prove yet aren't quite ready for the top league. I understand that this agreement is in place between the CHL and the NHL, this is just a hypothetical discussion.
In the case of the Rangers, a few recent prospects come to mind where this could have been beneficial. First is Anthony Duclair. Coming off a 50-goal, 99 point campaign, he had little left to prove in the Q. While there were definitely holes in his game such as defensive effort and consistency, I believe that it would've been more beneficial to both Duclair and the organization if he was playing in a top-6 role in Hartford while learning the organization's system and progressing with their guidance. To a lesser extent, this happened to Christian Thomas who scored 54 goals in 66 games, but had to go back and ended up with a disappointing followup campaign of just 34 goals when he could have been playing pro. As we all know or don't, he's essentially a tweener in the Canadiens system now.
I think this point is more relevant to a few of the most recent draft picks, Dylan Strome and Mitch Marner. Each has much more to learn and more physical maturity to go through, but the two combined for 255 points. But if they don't make their respective NHL teams and there's a decent chance that neither does, each has to go back and play Juniors for another season. They cannot even be called up to fill in for the team if injuries pile up, except in special circumstances (Brayden Schenn and LA).
Even if every NHL team only gets one per season or a certain number league wide, I believe that this is something that should be amended to the agreement. The CHL is the only league that has such a deal, as any player drafted out of the NCAA, USHL or Europe can turn pro and play in the minor leagues the next season.