apparently thats the reason EI aren't doing so well, by the time it lands back into DUB (late afternoon during the week) all the transatlantic flights have already departed so it means you would have to nightstop in DUB and catch a connection the next day - i have a few friends who had to do that, bit of a pain really, therefore think the ryanair slot suit people much better and generally are pretty busy flights.
ash666 DUB is a large airport! Quite a range of connections from DUB