I think that movies of the Bartimaeus Trilogy would only work if Bartimaeus had a distinctive voice throughout the movies.
They would also somehow need to include the footnotes in the film. I was thinking maybe the Bartimaeus chapters could be actually narrated by him, as in a voiceover. It would be cool if it went from the movie to footnotes and back again, for example in AoS when Bart is being guarded by Uttuku and he's talking about the battle of Al Arish, it could actually show the battle.
When it's just little footnotes maybe the movie could just pause so that the narrater (Bart) could say the footnote at the appropriate time. This is where most of barty's humour comes from in the books.
So if they did it right, it would make an awesome movie. If they do it badly, there's still always the books.
When I set out from the boy's attic window, my head was so full of competing plans and complex strategems that I didn't look where I was going and flew straight into a chimney.
Something symbolic in that. It's what fake freedom does for you.