Why include one? Including an Xbox One controller will increase the price $60 for... what? You won't be able to run Xbox games on this device. While lots of PC games do include controller support, this isn't universal, and most of them are third party and aren't great for pack-in. And it dilutes the messaging of this as a portable device.

I'm not dissuading you from your tablet gaming dream, but hook up an Xbox One controller to this and you'll get the experience you're proposing.