Well, Gon's already powerful, but he has a weak and unstable childish mind. You know how in most shounen the MC is a firm believer in the power of friendship from beginning to end and the only thing that changes is their strength? If I met a person like Natsu, my first thoughts would be "this guy's batshit."
Gon seems like the opposite of that. He doesn't need to grow stronger in power (see pic related,) but his development may just be growing out of the dangerous "shounen protagonist mindset" and becoming a more realistic and well rounded character. Gon developing a new hatsu at some point could reflect on how much he has changed as a person since a big component of nen lies in the emotional state of the user. I doubt he'll become an antagonist, but he definitely won't be like the typical manga hero. I hope he goes to Meteor City after getting his nen back. It'd be a good step foward in having him grow out of his childish ways.