This will probably be too late for 9, but maybe in 10.
The only problem with multinational leagues is that all players are created 'equal' - the league has an average level that players will be created around.
It would be nice if the world setup files (nations.txt, cities.txt, ethnicities.txt, etc) could be combined and allow for more realistic world-tinkering.
For example something like the following
probably looks naff in here, but each country can modifier the base ratings, as can each region if wanted, or a city...
These 'figures' would be used before the Player Creation Modifiers kick in, so in the example above Afghani players would on average have 50% more power but only 25% of the control of an average player, but those in Badakhshan have an average power of 25 due to them being slightly heavier (250lbs).
Ethnicities are also controllable at what ever level you want, currently it's only country wide...