While unions between nation-states in the same area, such as the European Union, are a key part of globilization, it is not feasible yet to remove country boundaries. No two countries are in the exact same place economically or have the structures in place to merge with each other, much less create a single global government system.
Nation states are needed in today's world. This is because so many people have their own ideas on what civilization really means. If more people could live in grouped nation states then they could create their own "world away from the world." As long as they are abiding by Federal laws, this would be a perfect solution.
Nation states are a good idea for any continent looking for government structure among individuals. The like the United States there are states with their own set of policies and laws, then you still have a national government that regulates overall. Europe had adopted this concept many years ago and it has worked out for the better.
National boundaries are of little or no use today. The corporate interests and bankers who are running the world don’t even pay attention to them anymore. Issues are not decided on nation boundaries anymore, they are decided by brute force and extraction. Boundaries once offered protection and sovereignty. They don’t anymore so they serve no purpose anymore.
To say that nation states are not needed, is not to suggest some free market, anarchist utopia. The only things that are needed is a stable environmental system in which humans and non-human animals are able to thrive. Neither nation states nor the free market are able to protect the living system, let alone provide an alternative one. In time, the Earth will show us just how unneeded nation states and this mess we've created, really are.