Do you realize that your example actually counters your point? The Greece's example illustrates that a misbehaving minority shouldn't have an outsized influence on the majority, which is a correct thing to aim for, I completely agree with you on that. But the current EU arrangement actually allows minority entities to veto majority's initiatives and improvements, exactly because EU is not fully federated. 1 member country can screech and blackmail 26 other members for any arbitrary reason, and they all must comply with this minority's ultimatum. If EU was a federation, majority would simply outvote any obstructionists.