I recently stumbled upon this interesting interview on Animation World Magazine that was conducted by Nancy Cartwright, best known as the voice of Bart Simpson, with fellow voice actress Candi Milo, who played Astro in the English dub of the 2003 Astro Boy anime. It's a fascinating look at the voice over industry.
On the second page of the interview, when asked about what her most challenging job was, Candi responds by saying:
"I think the most challenging job I have done was voicing Astro Boy on the revival of the iconic series. Astro Boy is the Mickey Mouse of Japan and it was an unbelievable honor to be chosen to voice this. The tough part was, because Sony did it in cooperation with Japan, the Japanese actress and I laid voices to picture simultaneously -- 65 episodes of ADR. Yikes! It was very hard to create character, place emotion and character arc within the confines of anime expressions; arched eyebrows, thin line mouth, oval line mouth. Another tough aspect of this particular job was not being allowed to audition for the role I created for the Sony feature film. It actually hurt."Obviously she has a lot of respect for the character and worked really hard on her role, although there were only 50 episodes, not 65.
I'm not sure if she is mistakenly referring to the currently in development Astro Boy movie by Imagi or the previous attempt at bring Astro to the big screen, which did not get off the ground. Sony did have the rights to Astro Boy, and a lot of work was done to make that movie happen, but I'm unsure if they had ever gotten to the point where they'd hold auditions. Obviously that movie never happened and Sony has nothing to do with the animated film that's coming out next year.
Anyway, while Candi's performance as Astro was well done, despite problems with the English adaptation, it's unfortunately not at all uncommon for film producers to not want much of anything to do with anyone associated with a cartoon version a property they're making a movie out of.