If they wish to preach that they are in it for development, then limit the number of 20 year olds to a reasonable number like 5.
Evening the board makes it better for competition across the league, 20 year old ex-OHL players are ineligible for NCAA D1 and are best to go CIS and use their education money. Same with 20 year old Jr. A players, had their shot go CIS and be done with it. They are not for the most part going anywhere higher now in hockey they had their chance, don't take spots of younger kids who can possibly move up the ranks in future whether it be Jr. A, OHL or NCAA D1 or D3.
20 year olds have to fit within the 5 player limit per team, otherwise move on.