I am a little baffled by the Krakow reduction, as there would be quite alot of "Irish" tourist traffic in addition to Polish migrants on that route. However, I guess there is also alot of competition!!
Aer Lingus dug their own hole with Krakow and traffic bled to Ryanair over the last 12-18 months because of some very strange decisions when it comes to diversions if the airport was closed due to fog/snow or some other reason that really annoyed the hell of out a large number of passengers who voted with their feet and left.
On a good few occasions EI bound Polish flights seemed to take a liking to diverting to Berlin over 500km away rather than the nearest open airport. I had a friend who was waiting for another friend in Krakow for a flight, and pretty much every other flight diverted to Katowice or another regional airport that day but the EI flight was the only one diverted to Berlin despite all other airports in Poland being open. This happened a few times last year from what I saw on arrivals/departure boards.
I myself got caught up in something similar in November 2010, flight to WAW diverted to SXF as WAW closed due to snow cabin crew told us that all airports in Poland were closed and had to divert to Berlin. Friend of mine waiting in Warsaw for me saw that the flag carriers were diverting to Lodz, Krakow, Katowice, Poznan amongst others, AL was the only carrier to divert outside Poland and the only airport closed was WAW and that was for just 60 minutes to clear the runway.
Fortunately for EI there is no competition to Warsaw so it didn't really bleed customers to FR on that route, but the Krakow one most certainly did.