There is room for one Scottish service to the western seaboard you would think. Nothing between Derry and Cork at the moment. EDI-NOC and EDI-SNN seemed to be the two most successful pairings when they existed, but then again if either was that successful it'd be operating today. The M6 and M7 are taking a lot of traffic away from SNN these days so previously sustainable routes from the mid 00's may no longer work from that airport, even with the apparently outlandish route subsidies they are now in a position to offer. Neither EIR or Flybe look too interested anyway so it would probably need to be Ryanair if it was to happen. Most likely nothing will happen before April 2016 at the earliest.