0
I bet we don't see John much more in the film than we see in the trailer. This isn't about John, it's about Sarah. Something I missed in my assessment that doesn't change anything but makes Future John's decision to send yet another T800 back less arbitrary, but no less cliche now, is that Skynet sends another T1000 back, this time to the '80s to kill Reece at the downtown LA department store so that he can never save '80s Sarah from the T800 encounter at Tech Noir.
So Future John sends a T800 back to Sarah's youth (and given that he's holding a bazooka or something when he rescues her, perhaps he's fighting off yet another Terminator in Child Sarah's past). That T800 saves her, becomes her Father Figure, trains her, and then fast forward to the '80s and Reece coming through, now she's prepared to save him. Everything from that point on is a flip of the script where she's saving Reece, erasing the events of the first and therefore second film. So then, perhaps, a trained Sarah and Reece can either prevent Cyberdyne from ever leading to Judgement Day, make a baby and then try to live happily ever after, or, stop Cyberdyne, make a baby, and train it to be the ultimate Future Badass because they can't stop Judgement Day and it's the only course of action in this never-ending game of checkers, not chess, with Future Skynet.
So, not only does this wipe out the events of the first and best film in the franchise, which is sacrilege of JJ Abrams and George Lucas proportions, it's going to mean that the second and second best film in the franchise also doesn't take place. If you subscribe to the notion that history can be changed, the filmmakers are taking a dump on the series. Insultingly and with no due respect.
It's less insulting if you see this as not really changing the past, just creating a new future in the multi-verse for Reece and Sarah, and it's all smooth and can still be viewed in a linear perception, because time is smooth and non-linear and it's only the limitations of our perception that means we move through time linearly and only see hints, through Relativity and Special Relativity, that time isn't linear. All we ever did or will do happens simultaneously and exists all at the same time and it's just our perception that sifts through this like the playhead on a VCR. This accounts for anomalies like precognition and allows for both the concept of free will and fate to be correct, depending on your point of view.
If it's a multiverse then that Future John will always exist and from his perspective, Reece always dies, BUT, that John never saved Sarah with a T800. A different Future John has that memory and he too will always grow up in the aftermath of Judgement Day and do his thing. At some point, one of these Future Johns gives another version of his mother a different future, one where his father is saved from that fight with a T800 but he too will always have grown up in the aftermath of Judgement Day.
"It messes with your head."