Just to add that even if the airside transfer was reopened you would still need to go through passport control there are three - one at the exit to each pier. The only way to avoid this is to choose flights that use only pier A but this is mainly domestic/UK and FR but with FR you need to go landside to checkin.

The problem is that DUB does not seperate dom and int paxs and doesn't use photographs as in LGW or MAN