In the past i noticed that when pulling out from my academy (Portugal) a youngster from very small countries (in terms of active manager number) i received better players. But really i think that this was only my impression. In fact, while i was pulling LA10+ youngsters only from "small" countries, there were portuguese teams pulling out many LA10+ portuguese players...
By the way, right now i am pulling only portuguese players since we have very few active managers and i want to fight for a good national team.