I didn't like the generic art style used in Twilight Princess, and I wasn't a huge fan of Wind Waker's since the atmosphere was sacrificed due to the lack of detail. I'm hoping for a Zelda game that uses an art style is influenced by the earlier Zelda games. Take, for example, this:

I think it offers a perfect balance between all the styles of the Zelda games.
But I don't want Nintendo to focus too much on the graphics, since I feel Wind Waker's gameplay suffered because too much time was wasted on creating a gimmicky toon-shaded look. So, if Nintendo just recycles Twilight Princess's artstyle, which will most likely be the case, I won't care as long as they don't waste time with pointless development that will take away from time they could be using to improve the story, gameplay, etc. (Example: delaying Twilight Princess for a year just to add Wii functions.)