could be worst
The Yanks could have Akira as a white American and have it set in New New York.
Though that would be part of the yanks lame Inferiority Complex (Heroes the series) where hollywood has bad guys are brits and good guys as white yanks. Where if you have another view its "UnAmerican" (the new xenophobia) or anti-american.
This aside from all the conversions of Marvel mags into TV/Movie content this would imply Marvel is best(cos its yank) then when that is exhusted use Manga and Americanize it to make it 'wholesome' (if it anint yank it aint worth s**t!).
So in answer to "Why can't the Yanks leave awesome things alone " is because they need reflected glory as they dont have any of their own.
This is what we have come to expect from LA - why would they change now!
Wait till they rewrite the bible and have jesus as a white republican from a sunshine state...
Ofcouse, imagine the out cry if you took an american 'hero' and recast him as a say a french muslim villian? Ideally black and gay.
Thinking of the screne play right now......