I think whether people will travel from Dublin or Shannon depending on price has a lot to do with the reason for the trip.
Leisure passengers will, business passengers won't.
Then you come down to who forms the bulk of the passengers on a route. On Cork-Amsterdam, it's definitely business passengers, who would pay more for a frequent service. I'd suspect that Paris would be pretty evenly split.
Considering that the Amsterdam route is almost half-sustained by interlining passengers, more frequency could introduce interlining options with the possibility of reduced onward prices, so it wouldn't even suffer too much for the price conscious.
I wouldn't even be too shocked if it happened on the Amsterdam route. If CityJet were ever to take over DUB-AMS, it would mean the end of the codeshare between Aer Lingus and KLM on ORK-AMS and I'd imagine in those circumstances that CityJet might also start an ORK-AMS service, because I doubt KLM would want to lose the 120-150 or so dailly passengers who are travelling onward with them.