I adored Superboy-Prime during his brief moment in the spotlight. I think the disproportionately vocal and grumpy fanboy segment of comics fandom is deserving of as much mockery and teasing as the venom, snark, and impotent rage they dish out on a regular basis. That said, the joke Geoff Johns was making with the character has been played out. I don't think there's anything left to say with Superboy-Prime, particularly now that the worst, most toxic parts of comics fandom have metastasized into something even worse than Johns was mocking back then.
Unless Johns wants to bring Superboy-Prime to say something new about that, I think it'd be best to let the character remain in limbo.