I see a lot of people saying things like "oh god, Zelda is cel-shaded again, I hate it! It looks like N64 graphics, everything is flat! Same old Zelda guys! They should have made it realistic!" and, well to be honest it annoys me. Here's why...
Firstly, there has only been one console Zelda game that is Cel-shaded, and that is The Legend of Zelda: Wind Waker. This is what cel-shading looks like...
It looks vibrant and cartoon-like, which really worked for the game at the time, and still holds up today. The Legend of Zelda: Skyward Sword however, looks like this:
Which looks more like a piece of art, and this is for good reason. If I remember correctly, Miyamoto-san said at a Zelda Round-table that Zelda's art style was inspired by impressionist and post-impressionist pieces of art from the 1800s.
Pieces like Claude Monet (the majority of his art I don't actually like all that much, but he did start it all) Paul Ceyzanne, and so on all spearheaded the impressionist and post-impressionist movement as a whole, which was considered radical for their time, as their art was less about realism, detail and perfection, and more about colours and vibrancy, broken brush strokes instead of perfectly formed lines.
Miyamoto-san also said that he was looking to change up the overall structure of Zelda. So think about this: Zelda has adopted a radical for it's time art style which broke through the widely accepted visual norm, along with claims of radical changes to their flagship franchise. After thinking about that, it should be no surprise that this style was adopted, and while you may not like it (it took me a while to warm up to it), the flat looking surfaces and textures aren't the Nintendo team being lazy, but them creating an art style that breaks the norm (being realism) you are used to, and in ten plus years time will still look beautiful, much like Wind Waker. The surfaces lack detail, in contrast to realistic games that are all about realistic precision. And to further prove them right, look at their concept art:
I have also heard the wishes for Nintendo to adopt a realistic art style, a la Twilight Princess, yet there are also cries for Nintendo to do something new with the franchise. Firstly, Ocarina of Time, hailed as one of the best games of all time, was labelled as such not just for the gameplay and atmosphere, but the dark and realistic art style that came with it. Same goes for Majora's Mask. Observe:
However, while this is all well and good, it has been done not once, but three times already. It is widely known that Zelda fans are impossible to please, with Twilight Princess being too similar to Ocarina of Time, and Wind Waker being too distant, but they all seem to be judged on how far away from that game they are, and I think we need to let OOT rest as a classic.
In fifteen years time, people will be talking about Ocarina Of Time, Majora's Mask, Wind Waker, and possibly Skyward Sword, but Twilight Princess? Nah. Taking the realistic route would be pushing it once again towards the N64 era games' style, darkness and realism. They did that already.
This Zelda title's art style is neither realistic nor cartoon-like, it's somewhere in-between. I think my heart sank a little also when I saw the art style for the first time, but I respect Nintendo for trying something like this out, it shows what kind of direction they're willing to take.
And...that's it I guess, for those of you who read this far? I'm impressed you sat through that, and I hope it made sense. So I guess...
/rant
EDIT Take a look at the trailer, and then take a look at the art above.
Firstly, there has only been one console Zelda game that is Cel-shaded, and that is The Legend of Zelda: Wind Waker. This is what cel-shading looks like...

It looks vibrant and cartoon-like, which really worked for the game at the time, and still holds up today. The Legend of Zelda: Skyward Sword however, looks like this:

Which looks more like a piece of art, and this is for good reason. If I remember correctly, Miyamoto-san said at a Zelda Round-table that Zelda's art style was inspired by impressionist and post-impressionist pieces of art from the 1800s.
Pieces like Claude Monet (the majority of his art I don't actually like all that much, but he did start it all) Paul Ceyzanne, and so on all spearheaded the impressionist and post-impressionist movement as a whole, which was considered radical for their time, as their art was less about realism, detail and perfection, and more about colours and vibrancy, broken brush strokes instead of perfectly formed lines.

Miyamoto-san also said that he was looking to change up the overall structure of Zelda. So think about this: Zelda has adopted a radical for it's time art style which broke through the widely accepted visual norm, along with claims of radical changes to their flagship franchise. After thinking about that, it should be no surprise that this style was adopted, and while you may not like it (it took me a while to warm up to it), the flat looking surfaces and textures aren't the Nintendo team being lazy, but them creating an art style that breaks the norm (being realism) you are used to, and in ten plus years time will still look beautiful, much like Wind Waker. The surfaces lack detail, in contrast to realistic games that are all about realistic precision. And to further prove them right, look at their concept art:

I have also heard the wishes for Nintendo to adopt a realistic art style, a la Twilight Princess, yet there are also cries for Nintendo to do something new with the franchise. Firstly, Ocarina of Time, hailed as one of the best games of all time, was labelled as such not just for the gameplay and atmosphere, but the dark and realistic art style that came with it. Same goes for Majora's Mask. Observe:

However, while this is all well and good, it has been done not once, but three times already. It is widely known that Zelda fans are impossible to please, with Twilight Princess being too similar to Ocarina of Time, and Wind Waker being too distant, but they all seem to be judged on how far away from that game they are, and I think we need to let OOT rest as a classic.
In fifteen years time, people will be talking about Ocarina Of Time, Majora's Mask, Wind Waker, and possibly Skyward Sword, but Twilight Princess? Nah. Taking the realistic route would be pushing it once again towards the N64 era games' style, darkness and realism. They did that already.
This Zelda title's art style is neither realistic nor cartoon-like, it's somewhere in-between. I think my heart sank a little also when I saw the art style for the first time, but I respect Nintendo for trying something like this out, it shows what kind of direction they're willing to take.
And...that's it I guess, for those of you who read this far? I'm impressed you sat through that, and I hope it made sense. So I guess...
/rant
EDIT Take a look at the trailer, and then take a look at the art above.