Great article here from the BBC a few months back on player development for those who are interested:
http://m.bbc.co.uk/sport/football/35054310
Read it a few weeks back thought it was interesting.
When I was doing my coaching badges a while back, my assessor, used to be part of the West Brom academy, and he worked with Ashley Williams, and he said, how Ashley used to be a striker, but had two bad years in a row, as he hadn't developed physically and was released at 16. But then look at him now, captain of Swansea in the premier league and playing at Centre half. You cannot judge players in how fast they develop.
It's all good bursting onto the scene as a 18 year old, but it seems to be that a lot of youngsters that do this go off the boil, Sterling, Zaha, Berahino. Haven't really kept progressing. Would rather see constant development, than an exciting prospect who doesn't live up to their billing.