With all the cards finally revealed, I have thrown together two ideas I'm really interested in trying this expansion. Spell mage and elemental mage.
It feels like they have really opened the doors to some older archetypes and new ones alike. Spell mage has not been superb since it's release in AoO, but I've always liked the idea and wished it was better. Maybe it is time?
Elemental mage returns with some interesting synergies. I really think that Elemental Allies will be good this expansion, given that Confection Cyclone basically guarantees that it will be completed.
There's a lot of room for improvements in this deck but I think it has the basis for something good. Firework Elemental and Al'ar may be cut, because there aren't a lot of 6+ mana cards to corrupt with and because... well, it's Al'ar. I wish it was better.
Anyway, just my thoughts, feel free to contribute ideas and constructive criticism.