I've had a vision of something that may not be possible, but anyway for the sake of guessing..
What if the NX dock isn't a dock as we imagine, but rather an add on.
They've been playing with wireless streaming so they have that, and many had the idea that it could be a reversed WiiU.
What if the NX is a portable, classic, with great ergonomic, and NO detachable controller. BUT, in the box, you have some kind of hdmi dongle that receive the signal AND an extension for the portable, like something you put on it's bottom, that has it's own battery, and adds power to it (thus their patent), AND the wireless streaming tech.
So you don't have the problem of needing detachable controller that will become something weird or having an other pad. You play the portable as you go. When you're at home, you just plug that add on and you stream it on your tv. The added power make it goes from 540p to 720p (cause you know it's not going 2x the power)