There is no such thing as other shooters for the CoD crowd. I'm part of that crowd (it's all I've played on 360 since MW1). Titanfall is the only hope at the moment. 

It would easily be one of the most asinine decisions ever made. Nintendo should seriously pursue trying to get some exclusive content for CoD on its systems but Activision should never exclusively put it just on a Nintendo system haha. I mean if Activision had to choose a system to solely put it on, they should do Xbox systems. Nintendo wouldn't even be a close second haha. Asinine not disastrous.

This.

Something would need to fill the void and target the millions who are willing to throw down money every year for the experience.

With less competition, other FPS games would likely grow, new developers would rush and fight to create a suitable substitute for the market, and even some existing franchises, that at one point strived to be fundamentally different to COD, would possibly adopt and replicate some of the games mechanics, to try and draw in portions of that very large and lucrative crowd. We've seen that already to some degree, but I'd imagine it would be taken even a step further.

No srsly, it would happen... because Nintendo's main audience doesn't care about COD (as proven by BLOPS II and Ghosts' abysmal sales), and long-time COD fans would sooner give up on the series or migrate to PC (if a PC version still exists) rather than play COD on Nintendo's inferior online network.

COD fans would just buy other shooters, there are plenty in PS4/xone that can replace it, so I dont think they would move to the WiiU

I'd want to see it happen just to witness the Nerd-Rage lmfao

This

EA pounces and has Titanrise released for PS4 in November. Titanrise and by that time Titanfall game of the year for Xbo. It becomes king and EA has finally beaten Activision and most of their games get worse, yes its possible.

It would help Wii U for sure, but destroy Call of Duty

People would buy Battlefield/Halo/Titanfall/Destiny/Killzone instead.