Ah the Aer Lingus service was a well-received and used service (to the best of my knowledge). Flybe having burnt their bridges on the SEN-DUB route so that they could save the LCY-DUB route (well, we think so at least), and that's now gone to the wall. So I think it fair to say that Flymaybe are definitely not flavour of the month on LON-DUB services...
Aer Lingus made it viable with ATR 72s (thrice daily sometimes as someone noted), and despite Flybe being able to tout their connections to the US through Aer Lingus, they simply couldn't make it work. A big managerial cock-up, frankly, Stobart should just do the sensible thing and go back to making it an EIR route as soon as possible.