Here's an idea that would help younger players contribute quicker, meaning top division teams could buy and train some of the best prospects. It would allow rookies to come in and play well much earlier, without giving them starting skills above respectable.
Basically, some percent of the time, young players would play with the skills that they could have when they were capped, or at least somewhere in between where they are now and where they could be. This would happen maybe 25% of the time for 18yo, 15% for 19yo, and 5% for 20yo.
I think this adds realism to the game, while at the same time making it a little more balanced. Players can come out at 18 and be ready to contribute. They may not be consistent, but they would do much better than their stats would indicate. Think about an 18yo MVP in D.IV, you can clearly tell from his performance that this kid is going places, but he isn't there yet.