I love Dublin. Its one of my favourite cities to visit too. I think there's just a certain type of person who visits & hates it. I'm not really sure what they expect to be honest.
Here's some things I recommend doing / seeing on a short trip to Dublin
The crypt of St Micans Church where Bram Stoker is buried. Super interesting tour.
The little museum of Dublin on St Stephen's Green. Interesting award winning museum in a Georgian house
Henrietta St Tenament Museum. Fascinating look into old Dublin on a beautiful old street
James Joyce Centre on North Great George's Street - another fascinating street & interesting museum
Trinity College to visit the Long Room Library & see The Book Of Kelks
Glasnevin Cemetary. Great historical important graveyard with loads of famous people
The Viking Centre
Christ Church & St Patricks Cathedral
The National Gallery
The National Museum
The Natural History Museum
The National Concert Hall
Several theaters including The Abbey, The Gate, & The Olympia
Guiness Store House Museum
Irish Museum of Modern Art which has beautiful grounds
The 1916 Museum inside the historic GPO
Drink coffee & eat cake in Bewleys a real Dublin tradition
Eat fish & chips in newspaper by Christchurch from Leo Burdocks traditional chipper
Visit St Stephen's Green & the Phoenix Park
Have a cocktail in the beautiful upstairs cocktail bar in Peruke & Perriwig on Dawson Street
Have lunch in the famous literary bar Davy Byrne's (features in Ulysses)
I could list another 20 things but hope this gives a bit of a variety of things you can go.
I'm not sure what else you might like to find in a city?