Do you still have your save?
I'd say if you didn't like the base game at all , there's no point in getting the DLCs.
Overall the DLCs tends to be better than the main game .
Jaws of Hakkon gives you an open map like the Hinterland .But the area has its own story , there's some cutscene , not a lot but some.Side quests are also better .Combat is tougher .It's quite long if you do all the things (at least compared to the other DLCs).
The Descent is a dungeon crawler in the Deep Roads.It's pretty straighforward , you go from A to B , but maps are big enough you can wander around.There's way more cutscenes.Some interesting lore and characters.
Also a couple of tough fights.What the Descent was really good at is nailing the ambiance of the Deep Roads , there's an epic feeling when fighting wave of darkspawn in what feels like a hellhole , but there's also a sense of beauty and wonders later on.
And finally Trespasser. It happens after the main game .
You'll spend quite a bit of time chatting with companions.So if you didn't like the companions....
Fights are also a bit tough in there.
It's a story DLC like the Descent (meaning you're railroaded from A to B in smaller maps) but contrary to Descent and Jaws of Hakkon , it's not a self contained story , it's the final chapter of the Inquisition.
Some of the music is really great.
It seems Trespasser is a fan favorite.
Anyway like I mentionned above if you really didn't like the main game at all...I'd pass.
If you didn't like DAI but you're a huge DA fan , there's some big lore discovery in Descent and Trespasser.
If you think you're going to buy DA4 , Trespasser tease you about future events too.