chicken

For highest level leagues like Spain, Italy and England, their national teams are affected more due to more EU players in their league. But they still benefit from more people outside their nations watch their league.

For lower level leagues like Protugal, France, Holland,... their naional team become stronger and stronger due to more players go to the highest level leagues. And their teenagers can get more chances in their local league.

So I think the only way to balance the situaion is more spain, english and italian teenagers goto other leagues to gain more experience... The best exsamples are Gattuso & Hangreaves.