I don't think national states should be abolished - most likely, attempting a forced change like that would fail atrociously.
Instead I think the concept of national states will slowly become more and more obsolete and redundant, while the national identities of the people slowly morph into something larger. In the case of European Union, there was a lot of grumbling about "losing sovereignty" when Finland joined the Union. Yet, these days most people consider the EU a positive thing by and large, and I think despite people here still considering themselves prominently Finnish, they are also starting to consider themselves Europeans in addition to their own national identity.* And this has happened within 20 years (Finland joined the European Union officially in 1995).
It's possible that national states will naturally morph into larger power blocks. United States is an interesting case, because they mostly skipped the national state stage altogether - even though they have states in name, their national identity is that they are americans.
Time will tell what will happen in Africa, South America and Asia. Africa is way behind the rest of the world because they're still so screwed up after colonization, they don't really have proper historically developed national states even, they have a bunch of countries with arbitrarily drawn borders and in some areas, governments have little to no influence outside their capital - the countryside being ruled by tribal communities, religious authorities and/or warlords.
Middle and South America have countries with strong national states and strong national identities, but the political instability will likely prevent close co-operation in near future.
Asia is perhaps the most interesting place for unification speculation. For historical reasons, though, I doubt many of the countries would be too keen on forming an union of any kind with China (North Korea doesn't count, it's an anomaly). China being essentially a totalitarian regime makes other countries probably very unwilling to have anything to do with them, and if you add the history between, say China and Vietnam, China and Japan, China and Mongolia, and China and Korea, India and Pakistan... not to speak of the general Middle East cluster****, I don't see any Asian Unification process happening any time soon either.
But Swifty has a good point. Liberal, democratic factions would probably not co-operate with totalitarian regimes like China, and would likely feel uncomfortable even dealing with countries with dubious democratic integrity (such as Russia).
On the topic of wikileaks, I find myself largely agreeing with Swifty on most counts. However I dont know if it should be in anyone's interests to keep their "bargaining positions" hidden in the first place. Open international politics could potentially reduce the amount of miscommunications and misunderstandings - after all, politicians are only humans as well.
Case in point, Vietnam War. I hear Robert Strange McNamara went to Vietnam in some anniversary celebration to the ending of the war, and ended up talking with some North Vietnamese head honcho about the reasons for the war. He asked why the Americans went to Vietnam, and McNamara told them they were worried about the Chinese growing their sphere of incluence, and that they went there to keep the Vietnamese free from Chinese influence. As the story goes, the Vietnamese guy asked McNamara if he knew any of the history between China and Vietnam, since those countries had been warring for thousands of years, and that the Vietnamese had no intention of slaving themselves to the Chinese. They had just ejected the French from the country, freeing themselves from colonial rule for the first time in a long time, and they saw the Americans as another imperialist invader that intended to colonize the country, so of course they fought back.
Over a million North Vietnamese dead or missing, over half a million wounded; about 220000 South Vietnamese dead or missing, over a million wounded; almost 60000 american troops dead or missing and over 300000 wounded, not to mention all the PTSD victims...
...all for a crucial, critical error of judgement and misunderstanding for the motivations of each party, and for the cause of the whole war.
Keeping one's bargaining positions hidden from the negotiations until you decide to put them on the table is sometimes a good idea, but it can also cause tragic misjudgements. Especially if both sides have the power to totally eradicate the other...
*One could argue that this "European Identity" has at least partially developed as a foil to the American influence on world politics during the reign of George II - especially the invasion of Iraq against the wishes of the United Nations (US justification for the war according to UN resolution 1441 hinged on the existense of WMD's which were not discovered and apparently never existed outside faked or "misinterpreted" intelligence reports), the practically unilateral support of Israel, general perceived attitude of "murricans", the willingness to act as the "World Police" even when asked.
Though, I have no idea if the UK citizens, or for that matter people in the old big European countries like Germany or France consider themselves "Europeans" in this sense.
