I would love to see THIS game on WiiU, but it was 2011 and only a demo. Do you think that the WiiU can handle better graphics than the demo ? 

http://www.youtube.com/watch?v=yjI3i7uFUBs&feature=youtube_gdata

Well, the past Zeldas always looked better than their respective system's tech demo, so maybe.
Also, IIRC the WiiU this game ran on was an older, Wiiker one.

I think it will look better, but different. Link himself, I think his clothes will look more realistic, but more stylized.

If it goes the Windwaker or Twilight Princess look I think it will look better.

Skyward Sword was a weird in between look that suffered for it.

http://3.bp.blogspot.com/-FZ_OA-ITDUk/UMtHx5cFc1I/AAAAAAAADIE/Ls0kZ7URz-E/s1600/Zelda+Wii+U+-+Nintendo+Blast.png

I talk about the quality not the style 

If it looks like the demo Im happy, especially if draw distances on Hyrule Field are purely amazing. Better to have these graphics and amazing large areas to explore than visuals that look crazy amazing and it be a corridor. Corridors simply dont suit an adventure game

Look better? Probably not. That demo looked good because of the high degree of effort that went into the art. Technically speaking, there was nothing there that couldn't have been on the PS3 or 360. It might have better effects but that will probably depend on what art-style Nintendo decides to roll with.

Honestly don't care, just as long as the gameplay is top notch as usual. I will say that the game will look stunning, like SMG was for the Wii.