It is always difficult to put fair and competitive teams together, even in actual team sports.Team concept tennis is a wonderful idea. But teams can be better thought out. Europe vs World isn’t an ideal concept.
I mean, every method is problematic:
European football: Unfair because money (often from sponsors or investors who are at a certain place very much coincidentally) gets the best players, and best players generate more money etc. etc.
US sports: Draft system seems strange and random, no real chance to identify with a team.
Even the football (soccer) teams in the breaks at school were mostly unfair.
It gets even more complicated in a single’s sport like tennis where a team competition as such looks weird and artificial.
Maybe I would draw by ranking groups, just like how the 2 groups in WTF are chosen, but this time they build a team together.