On the Wii U? Not going to happen. The period for large scale games being green-lit for the Wii U is likely over. Even some planned Wii U titles are probably being pushed back to the next console.
Also, who would Nintendo hire to build them a western military FPS? Anyone at that level would likely make a LOT more money putting a game on the PS4/XO and is likely contracted to a big-time publisher. No, Nintendo would have to build a new western studio--which, actually, they should have started doing a long time ago. Sony is at the top right now because they realized long ago that the future of home consoles depends on games developed by western studios.
If it were me, I'd look into making a new co-op FPS game in the same mold as Borderlands. That IP has been a huge hit, it doesn't depend on photo-realistic graphics, and it has good humor and great characters. I think that would be a better formula for a Nintendo console.
Of course, not of this is likely to matter, as Nintendo will probably continue to ignore western game development.
