As seems to be a common thought, I'd prefer Zelda Wii U try more realistic graphics. Think about it: the last Zelda game to do that (not counting OoT 3D) was Twilight Princess, which was somewhat lambasted because of poor color choice. The last "realistic" game before that was Majora's Mask, way back on the Nintendo 64. Translation: we haven't had a "realistic" Zelda game that didn't stir up controversy for the last twelve years or so. Zelda Wii U could be the chance to implement such graphics with much better reception, and the HD would bring that out all the better.
Honestly, I do want to see the graphical styles of The Wind Waker and Skyward Sword return at some point, because they were beautiful in their own rights and contributed to their respective games' charm. But after a constant bombardment of "different" graphical takes, I'd prefer we get back to realistic graphics if ever so briefly. It would probably help contribute to Nintendo's back-to-basics mindset as well.
My further preference is photo-realistic graphics the likes of Final Fantasy Versus XIII - incredibly detailed and beautiful, but not fully realistic, either. I wouldn't mind fully realistic graphics all that much, the more I think about it, as technology has risen to a level where it no longer looks stilted or goofy in any form.
To help visualize my ideal Zelda Wii U graphics, here's a Final Fantasy Versus XIII video.