Mithos
Member
I think expecting Japanese voices is a huge mistake unless it's a game without much dialogue. The fact that Wii U isn't using BR discs has a big impact in that regard, assuming it isn't just a licensing issue.
The "Wii U Optical Disc" Nintendo are using have the capability of 25GB, they do not support the Blu-Ray standard though, and can therefor not call the disc Blu-Ray. If the Wii U Optical Disc's can support dual layer or not is not known as of yet.
This is similar as how the Wii Optical Disc wasn't really a DVD, but had the same storage capacity.