I believe the Sky Temple has been renamed to Forest Temple, just like the Siren Realm is now named the Silent Realm.
I really hope the temples will have more dominating elements like as in OOT. I think OOT is the best Zelda game if it comes to the difference of atmosphere between the temples. Later games contained more neutral temples that didn't really contain any element.
It was like water, fire and forest where really well themed, but all other themes turned out to be more neutral in athmosphere that made it feel like just regular building with just different coloured walls and different themed doors.
Examples are:
Windwaker: Tower of Gods. Also the Forest Temple and the Wind Temple where a lot alike.
Twilight Princess!!: Temple of Time, City in the Sky were both quite neutral. Also the Snow Ruins where quite neutral since it was just a house with some frozen floors in a few rooms and ices enemies.
What I would like to see are temples with really different athmosphere's.
Forest Temple: a lot of grass, trees, veins, huge branches and even enemies that represent insect creatures and animals you usually see in a rainforest. The one in Twilight Princess is great.
Fire Temple: red rocks, lot of big boiling lavapools with clouds of hot smoke to almost make you feel sweat in front of your tv. The one in OOT is the best example.
Other themes than forest, fire, water, desert and shadow can also be implemented in that way.
Who says that an Earth Temple has so be neutral. It can be like a total dark cave inside with enemies hiding in dark rooms, stalactites and stalagmites, those waterdrops falling from the ceiling and strange lizard kind of animals that use to live in dark, cold and moist caves.
Same counts for an Ice Temple. Who says it has to be some neutral themed building with yetis living in it, like in TP? It can be more like OOTs Ice Cavern only then bigger and with scenery, music and a shivering Link that almost make you feel cold in front of your TV.
Even a tower of god-like/technical temple, who says it has to be just a building with walls with 'mysterious signs' on it and doors with the same 'mysterious signs'? I think Nintendo was way too carefull while designing the Tower of the Gods and The Temple of Time. It is a great theme to be outrageous with and even mess with normal physics. Make Von Escher like rooms, which are impossible to be real. Even mess with the law of graphity, like they did in MM with the Stone Tower Temple, only then in four directions intead of only two. The wii is a great system to implement such outrageous things.
So yes, I hope different elements are really implemented into the temple and deeply determine the atmosphere of that dungeon. No more neutral themed temples.