It presents an agile way to incorporate flashbacks into the present, which is a better storyline (than the past this movie creates) that should've been explored. Other than that, this movie is a travesty to the original story - by bending the myth this hard and seeking to explain every single sign of Norman's pathology, it becomes a parody of itself without understanding it.
Perhaps I'm crazy but this movie actually has good stuff in it! There's a scene straight out of Peeping Tom near the end, and the poisoning scene disturbs. Much more serious than the murdering in Psycho 2 & 3. The scene feels very carefully assembled much like the effect in Hitchcock's film: pulled into a ghost train of a dream. Olivia Hussey as Mother! not to mention the delicious deadpan acting of Anthony Perkins.