There is no need to cast american actors for this. They already did that with Dragonball and will do it with NGE (even changing the names to english ones). No one needs that.
Just let the asians do the movie (they can make great movies). Hollywood can always swoop in later and just steal the story (like with Ju.on aka the grudge).
What does Hollywood know about mangas? Nothing. Let the asians do it. The chances that they understand how to handle it is many times higher since mangas are a part of their culture.
Plus, they would cast unknown actors (which is better) that could actually look like the characters in the manga (asian looking).
Or even better. Do an animated version of it. Like the FF childrens advent.
If they did a Hollywood version of that film, it'd fail miserably at the box office. All the good stuffs get's cut out anyways.
Just look at DBZ. It's known around the globe and has many fans. Now a movie get's made. But what do we get? A movie without super saian action.
It'll fail and we'll never get a second one.
The asians should've done it themselves. Do it like the FF movie and you can do everything. Saians, their packed bodies (no actor looks like that) and even the faces can look like in the manga.
You'll probably earn more money that way and end up with a better movie.
PS: Adrian Brody as Katou? Sure, he can play a school kid convincingly.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"