I definitely believe Kairi needs to get in on the action. By no means should they make her out of the blue amazing at fighting but at least a basic knowledge would suffice. I think that in order for her to grow and for her friendships with Sora and Riku to develop she needs to be out there with them. I have a few speculations as to what her ultimate role will be, though.
*SPOILERS*
Speculations:
1.) I somehow believe that Kairi may be used like Ventus was in opening Kingdom Hearts because of the purity of her heart. I actually think this would be very gripping story wise and would add a lot more importance to her character.
2.) I can't shake the feeling that Sora won't pass his mark of mastery test for some reason. Ultimately, I think he'll have his own brush with darkness in order to develop his character a bit more as well. Point being, if this were to happen, Kairi would need to act as an anchor for him...keeping him grounded and surrounding him with light.
3.) Personally, if a Sokai romance isn't developing or developed by KH3 I'll be disappointed. Despite that aspect of the game not being vital, I think that with the characters growing up it's only natural for this to happen. Regardless of whether or not you support the couple, there have been way too many signs pointing in that direction to leave us without some sort of resolution with that. So I guess to sum up this last speculation is that I believe if Kairi is to have an ultimate role, it's as a love interest.
Again, all speculation...nothing that I even expect to be in the upcoming game but just nice to muse on anyways. I love Kairi as a character and I just want to see her used more!!
