This is like a theory I had before.
Kairi said "This time, I'll fight.".
The whole first game, she wanted to help, but Sora didn't let her.
Remember? In the Underground place? Sora told Kairi that she couldn't go with him.
I think that made her feel pretty bad...and have you seen how much more mature she looks in the trailers?
I have a feeling that during the year after KH, she learned how to fight, so she could help Sora find Riku and the King.
Maybe when she's looking out to the sea...she's not just missing Sora...she's trying to find a way to get to him?
And...I'd grab a pic-but I can't find it...the Sitting Unknown looks like a girl.
Well, the Unkown has feminine lips-but this is Square...guys look like girls.
Finally: Sora and Kairi sorta...have a connection. Their destiny's are intertwined, you know? Maybe she's just as incomplete as Sora is. That'd be interesting.