They absolutely NEED a nationality-diverse cast otherwise this movie could fall at the first hurdle.
Personally I have to be a little excited because of how much of an amazing year 2015 is for the film industry (Avengers 2, Jurassic Park, Star Wars VII, James Bond, Batman/Superman, Antman, Assassins Creed etc) and to add another title to that lineup is A-Okay with me.
Don't get too excited though, the Japanese film industry is VERY different and are hardly known for their skill in CGI, this could be the biggest disappointment ever.