Errr, V50...that's exactly what they are doing.
The ALT A330 fleet is officially based in SNN to allow for service like you described!
As to the logic of an A330 doing SNN-DUB...that's a bloody improvement over what used happen.
I remember in the late 80's (around the time that the JAL 747 crashed due to the total hydraulic failure brought on by the failure of the rear pressure bulkhead) Flight International produced an article suggesting that the failure occurred because the particular aircraft was one of the highest cycled 747's in the world. They stated that it operated the worlds shortest B747 scheduled route between Tokyo and (I think) Nagasaki.
I couldn't believe the gaff by such a reputable publication. I almost wrote them a letter.
The Tokyo-Nagasaki(?) route was twice as far as the scheduled Aer Lingus 747 service from DUB to SNN (and v.v.)
As someone else said...only in Ireland.