For business users it is very much an obstacle.
I am yet to come across anyone in the business world who has opted to fly into Dublin and take a bus for 3 1/2 hours rather than connect in Heathrow, Amsterdam etc.
It is a barrier to investment in regions outside Dublin.
Unfortunately, the role of Minister for Transport has been pretty much reserved for Dublin and its commuter belt in recent decades. That's probably understandable considering it's the only place in the country where transport issues will actually sway votes. However, with the parish pump nature of Irish politics, they have promoted the interests of their local area.