According to early reviews, Tecmo managed to really improve Ninja Gaiden 3 for the Wii U version but the game itself is still average overall.
The recent Nintendo Direct episode was released mostly detailing how the storage works on the system. Roughly 3-4 GB are used up for system purposes while the system can support as a maximum of 2 TB per USB port although only 1 external drive can be used at launch.
Nintendo confirmed SD cards can't be used to store Wii U stuff and instead are meant to store Wii related data and help with the transfer process.
http://www.screwattack.com/news/japa...capacity-wii-u