Hunter X Hunter
this is awesome. this is the type of expansion I've always expected from these manga. in fact, earlier today I was thinking about how in Naruto all we've seen is the world of ninja villages. It's easy to assume the strongest characters would be in those ninja villages, or the strongest characters would be hunters, or what have you. But why? at most these worlds are really only continents, or a fraction of the world as a whole.
Hunter X Hunter exploiting that idea is awesome. And while it's a tad kitsch, who knows if other continents around the world don't have their own 'Hunter' systems, concepts for nen, etc. It's like different nations forming their own fighting styles and technologies independently. If the next arc is Gon exploring the world, there's a lot of room to grow stronger.
I just don't want wars or anything. Keep to exploring, politics, rules, RULES, MORE RULES AAHHH
And a time jump could be cool. If people are put off by Gon and Killua separating, maybe pick up when they meet up again after a couple of years. Gon went off exploring in the greater world, maybe Killua went off in another direction with Alluka. There's a lot of material to work with.