To ignore any opportunities abroad is to go against all business logic.
Any "reasonable" opportunity. LGW was Fortress Orange with Monarch, Thomson and BA where EI brought nothing new to the party. Washington wasn't Aer Lingus at all as AerLingus231 states. Indeed the last long haul foray to Dubai didn't last either, long haul remains a relatively niche operation, which is fine so long as it stays in the black.
Aer Lingus is seens as Ireland's airline and trades succesfully as such. The record of these kind of airlines in other foreign markets is poor. Look at Air France on LHR-LAX or Lufthansa in Milan as Lufthansa Italia.