They don't even have to do much. They can release the WiiU version, and bring out "Extended edition" for other consoles. Then later sell those other levels to WiiU later. Or hell, they could just easily put "WiiU edition" on the front cover, and problem solved.
Lol. That would be a fun solution, indeed.
Ubisoft: look, guys. I know about your policy, and we're fine with that. In fact, we've got an entirely new rayman game for you. Exclusive, no less!
Microsoft: oh, really? That's nice of you.
Ubisoft: we'll call it "Rayman legendary"
Microsoft: is it going to be a follow-up?
Ubisoft: kind of. Look: here's some footage. A playable demo, no less.
Microsoft: is that a wiiu?
Ubisoft: this? no way! It's just our development engine. Nice Integrated Neuroncoded Team Environment Nash-Development Overmind, we call it. Or "nintendo" for short.
Microsoft: *not believing anything* right. this demo looks just like the nintendo demo.
Ubisoft: ...which in turn looks like rayman origins. Your point is?
Microsoft: this is just a cheap port with a different name.
Ubisoft: that's how you look at it. But on the plus side: we can release this new game in six months.
Microsoft: ...
Microsoft: I bet you reused over 90% of the code of rayman legends
Ubisoft: more like 99%. But that's how coding is: you don't want us to reinvent the wheel every time, right? I bet windows also reuses quite some code from previous versions! Also: have you not noticed that Rayman is now wearing a hat and that the Murphy-levels are gone?
Microsoft: that's just window dressing!
Ubisoft: in other words: just like windows millennium?
Microsoft: ...
Microsoft: can you at least put in some extra levels?
Ubisoft: we can make it rain in some levels. Is that okay?