i would have to disagree to a point on man u...because they do buy players more than having 'their own' players come up. the difference is man u doesnot spend like man c, chelsea, and others. man u does have financial backing from elsewhere, its just not from the middle east like man c.
i think there should be a ruling (similar to how german league was a few years ago) that limits the number of non-eu players on the field at a time. it should be something like x-number of nationals + y-number of non-nationals + z-number of nationals outside of eu. this would promote clubs to invest more in youth development instead of 'shopping around' for players.