There are many ways to look at it. One way is that the old non-unified Europe used to fight a lot, and the smaller states could be preyed upon. The unified one doesn't have these issues. Therefore you could see the EU as a Good Thing (in fact they won a Nobel Peace Prize for this). Therefore anything in the opposite direction is bad. Of course, things are not that simple.
In general, I think that society is slowly moving towards less borders and more global cooperation. I would be surprised if in a thousand years there are still 200 individual countries and governments. This step seems like a wrinkle in that trend.
That is my greatest fear for the far future. That Europe starts on a path that will lead to wars within a few decade.
Right now the European economic powerhouses are strong enough to thouroughly destroy the continent (winners and loosers alike) and probably a good deal of the worldwide economy.
Whatever happens that fear must not become a reality.
In general, I think that society is slowly moving towards less borders and more global cooperation. I would be surprised if in a thousand years there are still 200 individual countries and governments. This step seems like a wrinkle in that trend.