There are lots of places you can go with the concept, but only so many places you can go if you constrain yourselves to continuing that particular story.

The story was successfully completed with the original movie, but T2 took the concept and competently spun it on its head while continuing the story. After you've done that, what's left to do? Apparently only retreads of the first two movies.

Put another way, the series is oriented around Man vs. Technology (and more broadly, Man vs. Fate) and can't break from that or it becomes unrecognizable, unless you want to see John Connor consumed by inner conflict, or trying to survive nuclear winter, or organizing his fellow humans to protest harsh robot prison conditions, or I guess ghosts show up for some reason?

The only way that I can think of that you could flip it on its head again is by personifying Skynet as a humanoid robot protagonist who has a chance to work harmoniously with humans, but fate tragically works against it and the humans are mean to it and Skynet decides they all need to be wiped out. Or better yet, Skynet comes to love humanity but still needs to wipe them out for some greater good. So while it still sends out hunter-killer robots, it's real sad about it.

Or the resistance reaches Skynet and John Connor spends an hour in rigorous philosophical debate with it about the nature of man and machine, a la My Dinner With Andre. Which... look, I'm gonna be honest, I would totally watch that, but it would piss everyone off. 😂