hmm. i'm in general fairly flexible when it comes to canon and draco simply because there's so little in it about him, and i think that most of what constitutes my image of draco comes from fanon. if i a story is well-written i tend not to immediately think that it would clash with or seem unlikely in light of canon. that said, a lot of what you bring up makes sense, like that if lucius were really abusing draco, draco would probably act differently around him. as for lucius, i tend to not think about him, and i don't know if i have any sense of him as a character beyond someone who's cruel.

i think most of the abused!draco fics i've read don't feature lucius as the one who's abusing draco.

I don't go in for the stories where the element is just thrown in to make me feel sympathy for the characters

that's certainly not the case with the cicatrix cycle. the abuse is def. a plot element, or rather, it contributes to a significant plot element. she handles it in a way that does justice to the topic.