I'm not sure I agree here... Even if they play in a mixed regional league, I would still think countries would want their own national team. With the language barrier and all, it may be hard for a Japanese manager to control a national team with Vietnamese and Malaysian players, not to mention oversee their development. I would feel that the solution that would work more easily would be with just a mixed league I, and then each league II would be just for a single country. That may preserve interactions between different managers of the same country. The cup is a minor thing, you can put everyone together. There may be the argument that "country A has less managers than country B, so they can get to the top league more easily", but then what can we do?