Golems of Amgarrak: The whole thing is over way too quickly, and it's not tied to anything relevant or interesting so it's hard to care about what's going on. Also, back-tracking with the different "color switches" was annoying. But at least it was actually challenging.
Leliana's Song: Alright, this one's actually pretty good. It's nice to get some backstory for a character that actually mattered in the core game, and it even has all the elements that make DA:O fun, like dialogue, looting, leveling-up, allocating skills, and an actual story.
Darkspawn Chronicles: It's almost impossible for me to care about winning a hypothetical battle as a darkspawn vanguard, especially when the entire thing is just straight-up combat. And the combat's not even fun because you're low-level and just use the same skillsets as an average warrior.
Witch Hunt: It doesn't last very long, and most of the game is basically fulfilling an arbitrary side-quest that has nothing to do with Morrigan. She makes a brief appearance at the end, but it does nothing to satisfy our curiosity about what she's been up to and offers zero resolution to her character arc. Oh, and all of the locations are recycled.
So, yeah.... color me unimpressed. But at least I'm finally done with all things Dragon Age.