Well, considering that the battling system has supposedly been upgraded, there is no doubt that the physics have changed. In that same trailer, you can also see how while Sora is attacking, he doesn't decline. My guess is that your character only declines while he is idle, meaning that much bigger combos are possible. I bet that not only will it be easy to strike your enemies with a spell after you've killed half of them, but it will probably be possible to attack even after you've cast the spell.
Seems like SE has been focusing more on air-attacks. ;D