It seems like practically a foregone conclusion at this point, so let's just assume NX is a home console launching Holiday 2016, and that Zelda Wii U will be released more or less simultaneously on Wii U and NX at that time, as with Twilight Princess on GameCube and Wii ten years prior.

What will be the selling point of the NX version? What will be the major difference between the two?

For reference, Twilight Princess featured light motion controls (pointer for ranged weapons, waggle for sword attacks), an arbitrarily mirrored game world, and I think widescreen support? Because it actually did not support the GameCube or Classic Controller on Wii, and therefore lacked free camera control, dual analogue for ranged weapons, and simple 'B button' sword swings, the GameCube version is generally considered the superior or at least definitive version of the game. Will the same be true of Zelda Wii U -- will the NX port actually be considered a slight downgrade?

Maybe it will have online multiplayer because NX will have better account systems lol

Its hard to predict what it will have more of beside beter resolution since the NX can be a traditional home console or something totally unexpected again.

Assuming the Wii U version can't do 1080p at 60FPS, then maybe that could be a major point?

I guess one major difference between the GC and Wii was their controllers, and that they were radically different.

I don't expect the controller of the NX to be too radically different from the Wii U's Gamepad or Pro Controller, so I'm not too sure if there will be a huge difference in controls either.

Playable Cranky Kong

Either better resolution/lighting and textures, or both that and higher framerate.

I say graphically since the NX should be more powerful than the wiiU one would imagine. At least with the wii, the motion controls could be considered a selling point in the eyes of Nintendo and 16:9 is awesome as well but provided the NX has a similar control scheme as the wiiU, Nintendo may feel to need to enhance it some how. So most likely, the graphics will be improved. Or perhaps it will be 60fps instead of 30.

So yea, there are many others ways that Nintendo can really improve the NX version compared to the wiiU version and before people give the whole "Its not Nintendo like" nonsense, it's not Nintendo like to not have an exclusive Zelda U on a console....

And its not like the wiiU's controller can't be improved either cause the NX can also have press sensitive triggers and who knows what else. Maybe there will be a cool way to integrate the handheld with the console or something more unique. The issue is that we don't know what the NX is going to be, we can just speculate

1080p and 60FPS and maybe some new features.

Better resolution, framerate, and textures / lighting all at the same time is pretty optimistic. Not only is that a lot of extra work to put into the NX version, it suggests that the NX will be dramatically more powerful than the Wii U.

An additional jungle area with Hyrulian amazons and destructible clothing. ;)

Probably better graphics and framerate.