Slow cooking them in the NHL might be the best path. They have access to the best training facilities, nutrition guidance, and coaching. The idea that a player has to be in 75+ games per season to develop is a North American notion. Is Cozens likely to get bigger and stronger playing 40-50 games and practicing with the Sabres while under the close eye of the training staff at the Harborcenter or by playing a grueling WHL and international schedule? If the Sabres did that with Cozens, there would be a PR problem, fans and media would be constantly complaining why he isn't playing more, his junior team would lose a big draw, and he might not be released for international play (see Jay McKee). It would also use a roster spot, and most significantly would burn a year of his contract. You send the player down if he's not ready to play a regular shift because you don't want to alienate the feeder leagues or have the player become an UFA a year sooner. Joe Thornton was slow cooked in the NHL. It didn't ruin him. But a lot of people weren't happy to see him sitting.