And how will it be done?

Let's be creative.

it's already there. It's called Coaster Crazy Deluxe.

Mario Kart... allowing us to see the behind view on the gamepad

Nintendo Land already does

I thought Nintendo Land did a pretty good job of this. I mean, it took advantage of the buttons, sticks, mic, screen, gyroscope, etc. The only thing I can distinctly remember it not using is that NFC rectangle in the lower left area.

I think Project Cars could do it. Basically offer Real Racing 3 with some physical controls, better content, and no freemium bullshit. I can see some people wanting to play on the big screen with status data on the pad, and vice versa.

...That's actualy really cool, damit!

Zelda uses it to select the inventory items quicker right? For me that's what it's all about, convenience. Personally that's better than something like a rear view mirror which can easily be put on screen (which is much more intuitive than looking all the way down and indeed less like a real car since the mirror is in the upper right not below you). I like not having to scroll through menus or have clutter on the screen. If you can put my ammo, health, etc. on the gamepad along with some inventory so I don't have to scroll through menus unintuitively like in previous Zeldas then I'll be happy and call it a benefit to gaming. If I have to steer or do sniping on it or something gimmicky like that then I'm going to call it stupid because to me that is forcing the controller on people like when you had to waggle to spin in mario or roll in DKCR.

Um.. Nintendo Land?

Pikmin 3 integrated it pretty well, without trying to use it for everything just to use the gamepad.

And Rayman Legend.