According to a very recent Facebook post on the official Wii U page, Call of Duty: Ghosts has been finally announced officially for the system. The post reads as such:
On 11/5, Call of Duty: Ghosts arrives on Wii U with an all-new world, story, and powerful next-gen engine.
For months, Activision has been seemingly indecisive on whether or not Nintendo’s Wii U would actually receive the latest title in the best-selling Call of Duty series, even though it had already been announced for PC, Xbox 360, PS3, Xbox One and PS4. The post also mentions that Call of Duty: Ghosts on the Wii U will be using the next-gen engine, the same one being used by PS4 and Xbox One.