I generally try to resist forcing 21st century interpretations on situations from an earlier era
I don't think it's forcing a 20thc interpretation to point out that it's not just Dean Priest who sexualises the thirteen-year-old Emily, it's other characters, male and female, and the narrator, who is always insisting on the slender, purple-eyed, 'love-curled', faun-eared appeal of her heroine.
I adore the entire trilogy, which I find darker and odder than the Anne books (LMM much preferred Emily to Anne, and moaned about being 'dragged at the cartwheels of the detestable Anne'), but for me, Emily is a pain.
She's a crashing snob, continually conscious of being from the locally-aristocratic 'New Moon' lineage, completely humourless, and massively melodramatic. You want to tell her to calm down and have a cup of tea. If she had a Tragic Scar, she'd grow up into the same kind of high-octane dog-poisoning lunatic as Teddy's mother. 
And yes, Ilse's father is a monster, but I think what bothers me is that the first novel asks us to believe everything is suddenly fine because of the discovery of Ilse's mother's body in the old well, which apparently jolts Dr Burnley into paying more attention to his neglected daughter, as though that's a happy ending -- the idea that it's somehow 'better' that his young wife died, possibly slowly of starvation, down a well, rather than ran away with another man!
I do like the dark, Gothic element, though -- the scene in Emily Climbs where the elderly madman with the birthmarked hand chases her around the locked church, or the genuinely unnerving sequence when she has a moment of second sight in her sleep and finds where a missing child is.