I hope and believe that there will never be a government for the whole planet until such time as there is some entity off of the planet that we need to negotiate with as a united planet.
One powerful government per country might not be perfect, but so far, it seems to be better than anything anyone else has some up with. The alternative is not some imaginary perfect government, but a lot of little competing governments/militias that probably pay even less attention to what anybody not a member of them wants.
I think one government, or rather something like eu, but for whole planet, will be useful, and it will be possible when live standards for people in different countries becomes the same, and old feuds are forgotten. However that's not something to happen in near future and i do hope that mars will be colonized and become off of the planet entity long before that:)
The problem with one powerful government per country is that different countries still have different powers and they like to meddle with weak ones, like US and Russia did in this case.
One powerful government per country might not be perfect, but so far, it seems to be better than anything anyone else has some up with. The alternative is not some imaginary perfect government, but a lot of little competing governments/militias that probably pay even less attention to what anybody not a member of them wants.