I guess I would enjoy Edgar Alan Poe much more if I didn't have to read him mainly for academic purposes rather than entertainment
One of my first essays at the university was about "Tell tale heart".
I don't read too many gothic / dark literature, but I enjoyed Stephen King's "Misery" a lot.
If it comes to LBT stories I do think that they can be improved if they include some degree of "dark" matters. I cannot claim to have used anything dark in my earlier LBT stories, but the one I've been writing for too long a time now has a focus on the rather matter of racism and it does include some violence. It is a thin line though that separates LBT stories with an LBT like degree of dark elements (e.g. the Pterano incidence, the death of Littlefoot's mother, the (rather lighthearted) execution of sharpteeth in LBT 6 etc.) from stories featuring LBT characters combined with a degree of violence and brutality that turns the story into a very different genre.
There is not (and never will be) an agreement where exactly that line between a "proper" and an "improper" degree of dark stuff in LBT stories is running. This always depends on the minds of authors and readers. There are just a few things which we can be quite sure would not have been in any LBT movie (including the earlier ones which were not as "childified" as some of the later).