It would be easier to get Junior Hockey to age restrict to a younger age than it would for NCAA to put an artificial age restriction in place, which really doesn't exist in NCAA sports. The only requirements are that you have not burned your amateur status in the sport and you be enrolled in the University. It is only natural that with Junior Hockey being what it is that teams would want players to come in older and more seasoned before they join their teams, except for the especially talented players.
I'm not sure to what extent it is a problem. Top picks that are developing well generally have no problem earning high roles and excelling. From 05-births, only Brady Cleveland, Salvatore Guzzo, Alexander Weiermair... and arguably Carter Slaggert seem like they are struggling to keep up on their respective teams. That's out of twenty-nine 05 births, and if you add in Celebrini as an 06 that's thirty total. The others range from doing alright to among the best players in NCAA Hockey. I would say it's more an indictment on the guys that are struggling that they just may not be ready for college hockey yet.