The latest trailer explained details of Dual and Double system which distinguished itself by partnering your main characters to in game characters to achieve different effects. Double system is more like "Unite" in Suikoden which two characters are paired to attack as one while Dual is more like a support where characters could take a hit just to save the his or her partner.
I'm not particular with the battle system and whatsoever as I concentrate more on the story. Though having a good battle system contributes a lot to the game's success, I still view games similar to anime, the only difference that each one has is that I can have the control and I can finish it the way I want it. I hope that there will be a North American release for Fire Emblem: Awakening as I can see the game as a perfect candidate for summer purchase.