I think I understand and share most of your reservations and disappointments with the film, though they don't affect the overall film for me that much.

From Ozon I haven't seen his newest, and "Water drops on burning rocks", yet (along with some of his shorts - he really made a lot before starting feature films.)
My favorite so far would be "Under the Sand" , followed by his short "A summer's dress" (which I didn't care for at all, when I saw it the first time ).