I want to see the main characters join the Phantom Troupe.
Oh my God. That'd be cool.
Like if they took Gon's indifference to all the death he's seen and made that an actual plot point. As though he were actually insane and his affinity for kindness only really comes to the surface when the spirit of Shonen energy coursed through his veins at strange intervals.
And so they re-wired the vaccum with the mouth to suck all the main character stuff out of him and then he'd act the same as he usually does on this time he'd constantly not care when people would get their skeletons put into trash cans after being eaten by dogs or when other people's hearts got ripped out AS WELL as not care about the fact that Killua kills people.
So he's like half way there but he needs another push to get there completely.
And his first mission is to find parking space.