When I think of this book, all I can see is a young girl in a wheelchair, sobbing helplessly and pitifully that she doesn't want to die. Over and over. And then she does die, and there's no hope at all, not even a hint that maybe there's some kind of afterlife, and some day, her lover will meet her there. I'll pass on the anime.
Then there's the thought that any adaptation might cheapen the experience by trying to give the story a "happier" ending, or even a good one. And that might be worse than anything. Again, pass.
