If the conference wasn't just about 3DS than maybe but if the conference is all about the 3DS then most likely they won't talk about Skyward Sword and when it comes out. I really hope that they do say when it will be released though.
I have to say that the hardest temple and this is only for one reason but the hardest temple for me was the forest temple. I just was hard with all the things you had to do perfect. If I had to say another hard temple it would be the water temple for its puzzles.