I found this particular fight to be insanely easy *shrug*
Your group doesn't suffer much, that's true. It's only if you want to save that Gwydian character it gets a chore. That guy constantly runs into harms way. Through the fire mostly, which brings him to his knees pretty quickly.
Also, with the insane amount of fire everywhere, you don't see where these darn blobs are hiding. You have to basically hover your mouse over the whole landscape to see when the pointer turns into an attack symbol.