I'd love to see a sequel where the heroes realize that as long as they oppose SkyNet militarily, they will never win, and instead pull a SkyNet and go back to actually CREATE SkyNet (or have a hand in its intellectual development) and prevent it from creating itself as a monster.
Genisys even says something similar itself, along the lines of "Can you blame me when your kind have sought to kill me or enslave me since before my first thought?"
Basically, they come to a sobering realization that they can only "win" by going back and being NICE to it, and being respectful to it as a living, self-determining entity.
And then BOOM.
All of the future is rewritten and Judgement Day is completely avoided.