I've been all over Ireland over the years, but other than driving through for the ferry, Dublin had always been a glaring ommision on our itineries. DH never rated it so was never bothered about hanging around the area. (It does look good lit up when you get off the ferry at midnight!)
A few years ago we did a longer stay than our usual family visit and focused more on the east than usual. We camped by New Grange and after getting off the boat at about 7am, had time to kill until early afternoon. We had two young children with us, so drinking and Guiness tours were off (not that I can stand Guiness anyway).
We struggled. We did a tour bus which was good. The queue at the Book of Kells was too long for the DCs to cope with, so we hopped back on. We just didn't find it a very intuitive city to find things to do. It's not a great place to meander and take in. Most of the family friendly attractions were away from the city centre.
The rest of the holiday was great. Ireland's charm is mainly in its rural areas, although smaller cities like Galway have a great vibe too. I've always been surprised at people's enthusiasm for Cork city, but then visiting with a shop-phobic DH, and staying with teatotal relatives mean that I'm not in the best position to experience it, and for all the numerous visits to the county, have never had a night out on the city which would probably be a game changer. The area around Brown Thomas is well done up and feels more comsmopolitan than my experience of Dublin. A lot of Irish architecture can be quite austere in a functional Victorian way that is shared with British industrial towns and there isn't an abundance of iconic architecture.
I'd keep an open mind about Dublin and Irish cities for nightlife, but for families, I'm not enamoured.