How about we don't make Kairi a playable character...
No, just no. Stahp, right there, okay. It's too late for her.
Do you really think Kairi has it in her to be like:
People who have spent years fighting and trying to master the keyblade? I'm sorry, but no that's just awful story telling. There has been seven Kingdom Hearts games, and so far no strong characterization or focus for her what-so-ever, which is really sad since this is supposed to be our main female lead. It's too late for her to turn into some kind physical badass by the time KHIII rolls around.
It's like "Wow a Princess a Heart, a flawless personality, and a keyblade wielder, she's perfect"
No, that's bordering on Mary-Sue, and that's something that needs to be avoided. KHIII is supposed to be grand daddy end-all of the Xehanort saga, and people want to bring Kairi to the battle field? Really? Really? I know this game lacks female fighters (which this game CAN afford to do), but this sounds really desperate.