During a recent interview with Nintendo Life, the producer of the upcoming Splinter Cell: Blacklist, Liu Jun, revealed that offline Co-Op would not be present in the Wii U version of the game. He said the feature needed to be cut in order for the game to released alongside its previous gen and PC counterparts. The Co-Op exclusive missions would be playable online with another player, and if players wish to remain offline, the Wii U version will provide the ability to play the missions solo in order for gamers to not get skimped on the Co-Op story.
It is not specified in the interview, but it is pretty safe to assume that this feature has been cut is because of the Wii U gamepad. Nintendo has stated in the past that the Wii U is designed to support only one gamepad at a time, and the controls of Splinter Cell: Blacklist require using a gamepad, as that's the way Nintendo probably wants games for the Wii U designed. This is very similar to the problem Nintendo had last generation for the Wii. Making a console that requires an entirely unique control scheme and mechanic only serves to alienate third-party developers who want their game to reach as many players as possible. Very few studios, save for larger developers, are going to spend the extra time and money to rework their game's design in order for it to work in conjunction with the Wii U gamepad. Why do you think EA isn't designing games for the Wii U? When have they ever passed on a chance to make money?
This problem is a vicious circle, as fewer third-party titles means fewer consoles shipping. Fewer consoles shipping means fewer-third party developers want to design for the Wii U. Such is the reason why the Wii U version of Batman: Arkham Origins will not have multi-player. Nintendo's focus on the gamepad may ultimately be the reason why the Wii U will sell the smallest number of consoles compared to the other two this generation, barring some amazing console-moving game that millions are clamoring to play. And, no, it's not going to be a new Zelda game.
Splinter Cell: Blacklist will be available on August 20, 2013 for Xbox 360, Playstation 3, Wii U, and PC.