Where does it end? Why not have a separate national team for Bavaria as well?
So national teams would end-up being contrived rather than truly representative? A bit like the NZ Maoris in the Rugby League World Cup.
Because there would only be about four or five countries strong enough to track competitive sides. The other problem is that most of the meetings wouldn't have any home interest, so would be a financial disaster. Even if you went for a home-and-away format, it's impractical for the like of Australia and the US to ride home meetings.