I think this piece of art is great. It lets us know there's a new Zelda game coming for all of us happy fans, and there's going to be something we've never seen before, weather or not we can agree on what precisely it is. Honestly, I think the theory that the chick is the Master Sword is quite silly. At this point, there's been no storyline or anything, so I suppose it is technically possible, but the whole idea sounds strange to me. Though then again, Zelda games are known for having some quite strange elements. Considering in TP we managed to get fired out of a cannon into a desert, turn into a wolf, make friends with a creature from an alternate dimension, and make soup out of stinky fish, pumpkins and cheese, I don't think any of us should know what to expect from this game.
What I think might be kind of neat is to revisit an older game or bring it into context with the series. I noticed a few times ideas used in Zelda 3 while playing Twilight Princess, and to have another game with lots of travel to and from the Dark World would be cool, plus it might be able to explain the Dark World as having to do something with the Twilight Realm, if not the same thing. Of course, there's no backing at all for this theory, I just think it would be neat.