In an interview with Engadget, Mark Rubin talked about the challenges they face for developing Ghosts for 6 different platforms.
Call of Duty: Ghosts comes to Xbox One, Xbox 360, PS4, PS3, PC, and Wii U, and each of these consoles have different software/hardware functionality. For Xbox One and PS4, those fit in with the PC style of resolution and artwork, which allows the studio to make cinematic quality work then bring it down to each platform.
For the PC, Rubin says this year they will have the best looking PC version they have ever had for a Call of Duty game.
Rubin also touched about how the stat transfer will work. They are using DemonWare as the storage server for keeping all the data. With Call of Duty: Ghosts, you can go from ANY platform, and your stats will transfer with your Call of Duty login.
And for the Wii U version, Rubin said that Treyarch has a dedicated Wii U team who develops these WIi U games for Infinity Ward and Treyarch.