I'm less concerned about Efron, who I can take or leave, than I am about the supposed PG-13 rating. I understand that a live action movie that's likely to be as CGI-heavy as a semi-accurate telling of Akira needs to reach a decent-sized audience in order to have a shot of making back its budget, but at the same time, the original anime Akira (and what I've read of the manga) is uncompromisingly brutal, and there's a very real danger that even a well-considered PG-13 would run quite visibly into the limitations of that rating.
I'll wait for the reviews. I'm definitely not going to "opening night" this one.