I think they should make 4 different u21/NT teams: North America, Europe, Asia, and South America/Africa/Australia. Country you are in based on main team nationality, but they don't play the normal teams. They play a 4 team group stage then the top two play for championship.
This would be a viable idea on paper, but I think that country pride will not be prevalent, so people wouldn't do it as much. Also, Europe would probably be a good team because as a continent they have more people.