Seems like we're getting an item similar to the magnetic gloves in OoX and FS. This image shows Link having a previously unseen item assigned to the B button as well as something that looks like two differently coloured horseshoe magnets by the left of the screen. The video also has a harp icon popping up around 0:27-0:31, which I assume must be Link's instrument of choice in this game.
And as for the mysterious character, I initially assumed that it was a redesign of the Sword spirit or perhaps a mysterious helper à la Sheik, but the Sword Spirit's icon pops up a few times in the trailer and it doesn't look like this mysterious person at all. Also, the contraption he's sitting on in the trailer is shown to be attacking Link a few screens later, making it more likely that he's a villain of sorts.
Edited by Snow, 02 March 2011 - 04:01 PM.