As far as I can tell, the higher the national team is in the FIFA rankings, the fewer games the player has to have played in order to qualify for a work permit (I assume this is why Kalinic now qualfies). If that fails it's done on a points basis depending on which league they are signing from, how expensive the fee is, how much his wages are, how good his English is etc. Teams have got around this before by buying players and sending them to other countries where it's quicker to get EU nationality. But yeah, as a result they hope young English players will get more chance of first team football.