Are you for real, comparing Belfast to Cork, Shannon or Knock?
Why not Cork, simple fact is the Wed and Sat is useless for weekend breaks, business travelers and do we really see lots of tourists coming to Belfast in winter.
Not to forget you have a 2 daily BGY ex DUB, 1 daily LIN, and up to daily MXP ex DUB.
If it does operate it will be a one winter service only.
It's the only route from BFS which appears to have been poorly taught out, buck/spade and eastern Europe are workable any day and they have made an effort with Berlin to work for things such as weekend breaks etc.