Sora has an idle animation of looking left, then right, then left again. This is straight out of his Kingdom Hearts 1 idle combat loop, and returns in Kingdom Hearts 2. He has a bit better posture in Smash Bros., but it's nice to see the return of this animation.
Another idle animation has Sora spin the keyblade in his off-hand, which is somewhat reminiscent of the Wisdom Form idle keyblade spin.
Another idle animation has Sora twirling the keyblade in front of himself. It resembles the beginning of the Tinker Bell summon animation from Kingdom Hearts 1.
All in all, pretty good idle animations! I most appreciate the first one.