acctually a kaito thing may not be a bad idea. Of course I'm not saying put in his intro and past with gon in a film, that would mots certianly stink, but what I'm saying is if we did one on KAITOS's acctual past. It could be like a flash back and forth sort of thing where kaito challenges gon to hunt for something/one that related to his past, and all the while kaito's observing him (and most likely killua) we'd get flashbacks on his past. dip in a confrontation between him and hisoka and we may have a pretty cool film.
What would stink is that it would once again not include kurapika nor leorio, but hey its a thought. one I would hope dosn't completely come true, but maybe as a second film or something.