My biggest concern still, however, is how long the game will actually be, with the whole limited time aspect of it.
The developers said it will require multiple playthroughs to fully complete. It sounds like it will have a Majora's Mask quality to it in that you will experience each part of the world in one 'game' period with multiple playthroughs necessary to see and experience everything.
Considering Majora's Mask is one of my favourite games of all time - if it's anything like that with just as much impact within the game world then it should be gooooood.