Ryanair won't expand to the UK from Cork as they had East-Midlands & Glasgow PIK and they didn't do well. BmiBaby East-Midlands route was very poor also.
Cork has the main UK routes covered:
Glasgow - EI
Edinburgh - EI
Liverpool - FR
Manchester - EI
Newcastle - LS
Birmingham - EI
Cardiff - EI
Bristol - EI
London H - EI
London S - FR
London G - EI & FR
If RYR were to expand into the UK some of the routes wouldn't be operated daily as there a/c are to big to serve some of the routes and they wouldn't provide the flights at good times like EI are doing with MAN and BHX from Oct.
Its mainly people who live in Co. Cork who use the UK routes as Waterford has BHX, MAN and LTN. Kerry has LTN, L.STN & MAN as well as UK routes from SNN.
Cork - Prague was served by EI and CSA so that route won't return as FR are leaving Prague.
Malév Hungarian Airlines served Budapest and it was dropped and FR are leaving Budapest.
If you look at RYR routes from Madrid you see that they mainly operate to the capitial city of a country and some major cities eg. London, Dublin, Oslo, Paris, Rome, Brussles, Frankfurt, Milan, Venice & Malta etc.
Berlin would do well if RYR had it and the only route to Poland would be Krakow but W6 would have to end Katowice before that would happon. Milan BGY and Venice Treviso would do well as they did in SNN but they would only be seasonal.