Why don't you make a Serbian World test and see how it goes?
Didn't you read what Baudin said? Too expensive and requires too much manpower.
Honestly we don't need more regional servers further diluting EN. If they opened Serbian server then some other country would want one too, then another and another. Inno's time, money, and resources are far better spent on improving the game.
Like ch0pper said, part of playing on international server is meeting new people and learning new things. Personally, meeting people from other countries has opened up my stereotypically narrow American view of the world.