fabo->A330s can and do use Cork Airport. There would be no problem getting an A330-200 transatlantic. Aer Lingus have some concerns about turning them on Cork's runway, but expanding the turning circle is hardly prohibitive.
There are, however, two reasons we won't see Aer Lingus transatlantic from Cork. One is the lack of a Cat III runway and the other is the solid commercial reason that Aer Lingus have only a finite number of aircraft and they can be more profitably deployed in Dublin, especially when a Cork-based transatlantic service would cannibalise the customer-base of their own Shannon transatlantic services. The only way I could see Aer Lingus coming on to transatlantic out of Cork would be as a reaction if some other operator opened the route first.