"For Muramasa we decided to stick with the original Japanese voices and only localize the text," Shane Bettenhausen, Business Development Director at Ignition, told Siliconera in a post E3 phone interview. "We felt the game was deeply steeped in Japanese tradition, mythology, and culture that trying to dub it, trying to make something more Western is really not a service to the product."
"Who wants some goofy anime voices in this game?" Bettenhausen joked.
Longer interview at the link.