The problem I have with "single world" anything is that it has nothing at all to do with the people or the world, or making the world a better place. There is no altruistic reason for this, no reason to stop war, no halt to genocide, no cessation of doing all the stupid things humanity has done for a thousand years. If they wanted to create such a world, why not make it for free education? Free health care? Jobs for all? Stop the production of arms and ammunition worldwide? I figure this is every bit as reasonable as a centralized world government.
The reality is:
It's about money.
It's about business.
It's about greed.
It puts all the power and money in the hands of a few and makes it easier for businesses and commercial entities to access and control the flow of goods and resources around the world. Unless a "New World Order" includes a system to level the playing field for all peoples, it serves no purpose other than the aforementioned. Even if it did, it would never work; if a system of government like that actually worked, we would have started using it a long time ago.