My fantasy Harry Potter

This week marks the beginning of a period of double ecstasy for Harry Potter junkies, myself included. I have spent years trawling the internet to peruse other fans' tributes and theories, and now it's time for the fifth film and seventh book - to be followed by a few weeks' stunned absorption of whatever revelations JK Rowling unleashes as, in Harry Potter and the Deathly Hallows, she finishes off the story that became a phenomenon that became a mythology.

That said, I'm expecting the film - the Order of the Phoenix, which opens here tomorrow - to be a letdown. A mainstream cine-juggernaut calculated to succeed all over the world could never do justice to the combined complexity of Rowling's vision and my own fantasies. After being swayed by a cinema full of cooing kids into giving the first film a good review in 2001, I've reversed my opinion. With the exception of Alfonso Cuarón (who made The Prisoner of Azkaban, the third Potter film), there has been a disappointing cowardice towards the darkness of the source material, with directors lightly rehashing its surface details. It's the films that lead people to disparage Rowling as a writer of reactionary, derivative kids' stuff, as a mix of The Worst Witch and Tom Brown's Schooldays.

Rowling's work is older in mentality than the films let on, and with each book the depth of the backstory, the interconnection of symbols, themes and action, and the implications of Harry's identity are made ever clearer. In the novels, Harry's story is 99% pain, anger, hate, ambition and violence, saved by a spark of redeeming love. In the films, we get a mystery adventure with some diet angst - and, in the Goblet of Fire, a strange bath scene that prompted an "Ooh!" of surprise from the audience. The books' epic structure and issues of destiny, sacrifice, suffering and prophecy are collapsed into a few token lines.

Admittedly, speculative narratives are risky to film. The cool weirdness of Dune worked, as did the animated version of Howl's Moving Castle, by Diana Wynne Jones, an important author unjustly neglected by directors. Excalibur captured the high, dark drama of the King Arthur myth - but not as cannily as the Monty Python version. Hollywood also has a way of ironing out a story's radicalism: Ursula Le Guin disowned one adaptation because it made the characters all white when she had specified that they were dark-skinned.

Perhaps it's best to be grateful that Harry made it to LA at all. It's strange to contemplate a projected seven films based on an abused child whose biggest hobby is hunting down the guy who murdered his parents. And the idea of such a long series, usually the province of elite directors such as Kieslowski or Bergman, does betray a fan-like obsessiveness on the part of Warners.

My fantasy would be to see the series remade by David Lynch, complete with time shifts, character body-swaps and elliptical dialogue. Or Kathryn Bigelow, who could shoot this very male tale with her characteristic muscularity. Mary Harron, who adapted American Psycho with slick, creepy perfection, would wrench breakthrough performances from the young actors. Best of all (and least likely) would be David Cronenberg, whose lurking homoeroticism and yuppie body horror would easily accommodate Rowling's nimble mix of genres.

There's still time for Warners to change course. The best of the series so far is the Half-Blood Prince in which Harry develops a blatantly homoerotic interest, with the famous line: "Harry, however, had never been less interested in quidditch; he was rapidly becoming obsessed with Draco Malfoy." I'd like to see if David Yates, now filming this sixth tome, is brave enough to show that little fascination in all its glory.

Bidisha, a novelist and arts critic.