The problem is that all politicians on a national stage are utter sociopaths, just like the C-level executives of every large corporation. These institutions cannot be managed by people with real emotions and empathy; the scale of their operations make it literally impossible. We simply need to make it illegal for such institutions to exist in the first place, except ephemerally through collective action.
Douglas Adams had it right: anyone that wants to hold an office of power should under no circumstances be elected to such a position.
To impose a rule like "no national states" you need a world scale big and powerful organization. And somebody would govern it.
"You are walking along the beach. You see a tortoise laying on its back in the hot sun. You don't help it get up; why is that?"
Also, I think big and powerful government would implement very strong surveillance and stop any kind of revolution, even stop every nascent seed of revolution and control every communication medium. The acts of terrorism would be sufficient justification for an increase in control and surveillance.
So, as a summary, I think that it's a better idea to try to improve the system from within and peacefully, and that observing what happened in Serbia may be helpful.