I personally like the system we have in America where different authorities perform different duties. I believe when you get to the federal government and consider the different agencies such as the FBI, CIA, DEA, and so forth it becomes quite wasteful. However, I believe it is best for local authorities to only handle basic problems rather than all of them because it is possible for their to be corruption if only the local authorities are used and they have all the power.
While it is true that central authorities can be corrupt and backward and power hungry, it's not nearly as bad as corruption is at the local level. Also, if local government was given more power, things would fall apart in more rural areas. Can you imagine if some of these ignorant mayors had complete control? Disaster.
I think that the federal governments should be the main force that rules the world. This is how it is in most countries, and seems to do a good job. The best way is like we have in the US, where the state still has a lot of power, but not to much.
I believe that local authorities, rather than central authorities, should rule the world, because a local authority is going to more aware of what is going on in the local community. Knowing what is going on in the community, the local authority is going to react to it a lot faster than the centralized community.
The idea that a central authority can make better decisions consistently than the people on the spot, and that the central authority is always correct and should be followed without question has a name. That name is fascism. The entire concept goes against the ideas of freedom and small government that many of us admire and profess. Central authority is concentrated power. Power corrupts and absolute power corrupts absolutely.