There are 3rd party games that use the Wii U screen but do not for other consoles. So even if it is a cross-platform game does not mean they could not create optional Kinect features of the game.
But that's kind of the OPs point, right? Kinect features will have to be optional and not core to the experience--at least when it concerns multiplatform titles.
Could be optional or not. Now that the developer knows that every Xbox One will have a Kinect then it is their choice to make it optional or not. It could be a marketing that this additional feature only found on Xbox One for example.
Why isn;t the 360 on this list? That's the no brainer choice.
Forgot to put in the title but for the poll is for next gen consoles. PC shouldn't even be on the list either. So wondering if I had to choose which console to buy for what would it be. As I like many others probably will not be buying games for older consoles if getting the newer ones.