If Ryanair didn't come in on MAN, I wouldn't be too shocked to see an extra EI Regional aircraft.
EDI in particular and to a lesser extent MAN could take extra rotations. And there is a market for Cardiff from Cork, even if only 3 or 4 times a week.
There's also a gap opened in the South-West of England, although it would be hard to know where to serve. Newquay may be too thin; Exeter may be a bit close to Bristol. Maybe more rotations to Bristol could be in order.
However...
Some extra capacity could be created by not flying Ws to Shannon, so either allocating an aircraft to Shannon or allocating it to Dublin and flying Ws from there may also be options for Aer Arann.
Also, it remains to be seen what effect the Shannon incident will have. Will the aircraft in question ever fly again and what will the effect be on Aer Arann's finances?