The best chance for transatlantic at Cork is for the Cork Airport Authority to talk to Aerlingus as part of an overall package in relation to their Cork operations.
To their credit EI have undertook major expanasion out of Cork in recent years and will have a 4th Airbus there next year.
An A330 operation to JFK even three times a week would attract many customers who presently fly via LHR and AMS as well as those who fly with CO to New Wark from SNN.
However the CAA would have to be generous with their marketing support for such a move.