I am afraid the average joe in norn iron is a creature of habit. When they go on holidays they want the same old same old as they had last year. I doubt there are enough people in NI to support any curve ball routes unfortunately
The arrogance is unreal. The fact is that with previously cheaper options south of the border and routes to every corner of Europe, people from NI will fly from Dublin. Within my social circle I could count probably 20 people (40 seats) travelling to Lisbon/Copenhagen/Toronto/Geneva from Dublin this year, and that's just the ones who have disclosed their airport choice.
With the pound vs euro the way it is at the moment, I wonder if Dublin is as cheap on similar destinations served from Belfast thinking New York? Also I wonder if Belfast is proving tempting to Southerners on a price comparison with Dublin. (Sorry Dubliners don't travel to Palma, Malaga etc as they are so sophisticated)