I think there's a bit of a gap between what you want, and what's realistic.
Yes, I agree that there should be a desired aim of having players such as you describe... however given the reality of our nation, you simply can't expect to completely fill the U21 roster with players that are going to one day play in the NT (even given the number divide which means that can't happen).
http://with-malice.com/ - The half-crazed ramblings of a Lakers fanatic in Japan