Why doesn't the EU just eliminate its import duties?

 Re: EU seeks "time for reflection" after Vilnius summit failure

I found this statement by EU Commission President Manuel Barroso to be particularly insightful:

"This Agreement would save Ukrainian business some €500 million a year just in import duties,” Barroso underlined after the summit...

By this statement Barroso admits that the EU is a closed shop; i.e., a supposedly free trade zone inside the EU but with high tariffs to imports from outside the EU. If Barroso and the EU really wanted to help the citizens of Ukraine and provide another source of goods for citizens of the EU, then the elimination of trade barriers would be an easy and important first step. But then Barroso and the EU would have no leverage on keeping current EU members. Why belong to a high regulatory, high tax, socialistic transfer union when one can trade freely with its members anyway? This demonstrates that the EU really provides no additonal value whatsoever that a country cannot achieve simply by unilaterally declaring itself to be a free trade nation.