You probably heard already, but they are trying to get the kid from Harry Potter as Shinji...
I hold the manga as a substitute. It helps the series. In volume 7, Sadamoto really went into Kaji's past, and IMO... made him a more interesting character. Kaji's past was held in the dark for a majority of the series and his intentions were never clearly defined. The manga fixed that.
the kid who played in sixth sence woudl be good actually in this role