There are positives and negatives around the EU.
I was once shown a graph in an Economics lecture which showed the cost of the Common Agricultural Policy in comparison with income from farming. The cost of CAP just keeps on rising, whereas income from farming just keeps on falling. The CAP is just a huge, massive drain on money - a pointless subsidy to keep farmers sweet in Western Europe. There is also a major issue over lack of democratic control over much of the EU. While the Parliament is democratically elected (although whether a list system is truly democratic is an arguable point) the real power in Brussels sits with bureacrats who are cossetted away from the realities of the member states. It's interesting to note that even in countries which are generally pro-EU there have been numerous anti-EU referendem results, with countries like France, the Netherlands and Ireland voting down proposed treaties. I'd suggest that tackling this democratic deficit is an important task in future with regards to the EU.
However, there are positives to the EU - as an institution it has helped enormously the transition to a more liberal democratic society in the former Soviet satiellites and former fascist states. Within the EU it has lead to more liberal immigration, reduced border controls and freer movement of labour and capital - all positive developments. Of course, the flip side of this is that while within the EU there is more freedom, the EU leads to a kind of 'Fortress Europe' stance, with protectionist policies adopted with regard to trade etc.
In the future I think the EU should focus on areas that really require cross governmental co-operation to address, rather than looking to inplement more regulations and directives in it's member states. This can be done by increasing democratic accountability within the EU system and bureaucracy.