That's cool. If the film is planned to be similar at all in tone to Prisoner of Azkaban, then he seems like a perfect fit. Azkaban was definitely one of the best Harry Potter movies, and certainly the most well rounded. After Azkaban they got a little too dark for what they were in my eyes, especially Goblet of Fire, which was just unnecessarily angsty. That tone only felt justified in the Deathly Hallows movies.
...oh, he's not doing it.