In my opinion, the coming together of all countries of the world to form a big government will in no way bring economical development to all. This is so because of the following reasons.

The presence of language barrier will be seen to play a key role in such scenario. People of one language will always gravitate to each other. Thereby creating division in the big country. This could be clearly seen in the case of Nigeria.

Secondly, looking at the operations of United Nation Organization(which could be seen as a symbol of the "big" country), it is obvious that priorities are given to certain sections while other sections get lesser priority.

Thanks @smyle

@largerben