See the Flames and Edmonton. That's exactly what they do, rush high draft picks into the NHL without letting them develop fully. Nugent-Hopkins is an exceptional player, but he already has a couple of injuries in his very short career because of his size and weight. It would have been much better if the Oilers just let him stay in Juniors 1 more year and hired a special dietary coach or something, to fatten him up and get him bigger so he's ready for the big club.
Same thing with Monahan. Great player, but rushed too early (I think) and is now injured.
There's a reason that Detroit, one of the most dominant teams of the last 20 years, took a long time developing their players.