Cork Dublin is probably finished as an inter city route. However a feeder service for long haul flights to North America and the Middle East would be well supported as driving to Cork after a flight of this duration can be very tiring if not dangerous. A stand alone operation by Aer Lingus Regional without competition from Ryanair is worth a try.
Is there really a need for such a service given that Cork is already connected to other airports that have a much better frequency and range of services than Dublin.
The only benefit of Dublin is pre-clearance to the US. However, in the wider scheme of things, Dublin's range of long haul services is quite small - with the connections Cork already has, I don't think there is much need to set up a route to connect through Dublin.