I hate the word "game changer" because it's so hackneyed and over-used now, but the A321XLR is a very interesting aircraft; have a look at the range ring from DUB:
Great Circle Mapper
At 4,600nm, virtually the whole of the continental US (and ANC!) and Canada are covered and - if EI were feeling even more adventurous - there are a few potential eastbound markets open to them.
The big challenge now will be to ensure that infrastructure at DUB can accommodate this fleet growth.
How many A321s (excluding the three currently operated, but including the imminently arriving A321NeoLRs) is EI now committed to?