Why do you need a One Nation World?
The idea seems a bit redundant to me. There are already supra-national rules that most, if not all free trading nations follow. They are out of balance at the moment and are being abused by the so called 'globalists' who are basically immoral global capitalists.
If we can balance these rules out everyone can have their own nation that plays fairly with every other nation. We can have both a national and a global world.
The other problem is that the global economy is completely out of balance in terms of balance of payments. UK and USA spend a lot and have huge national debts. China and Germany save and export more. This needs to balance. It makes sense for China to move their economy more to a service economy and for the US to beef up it's manufacturing. MOre balance is better for all.