It's not a major issue, but it's just one of load of silly little issues that combine to make rail travel in Ireland worse than it could be. There are a load of minor irritants like poor signage, random stopping points for short trains, catering trolleys in doorways, bad or wrong PIS information, etc that Irish Rail simply can't be bothered to get right and all combine to make things more difficult for the passenger than they need be.
It's fine for people who travel a lot to be able to recognise that the carriage with a big bit with no windows is the accessible one, but it isn't so easy for the person with poor eyesight who might take the train twice or three times a year for hospital appointments. While operationally arranging trains to be consistent (which doesn't seem to beyond most railways) is a problem for Irish Rail, how difficult would it be to apply significantly bigger decals for wheelchairs and bicycles?
The bicycle thing is a bit of a safety hazard as well as you frequently see eejits cycling up the platform at intermediate stations when when they've guessed the wrong end.