If you were asked to make a terminator movie, what story would you craft?

A terminator is sent back to prevent the assassination of Miles Dyson thus keeping the future of Skynet on course

A space Terminator is sent back in time to prevent the asteroid collision that wiped out the dinosaurs, allowing the terrible lizards to stay on top of the food chain and thus prevent human evolution from ever taking place.

Thus no John Connor.

I would show the human's complete and utter defeat. As what would happen in real life.

A terminator is sent back to stop a serial killer from killing people at a nudist resort. It would be done in an exploitation B movie style with a sci fi twist.

Make it as a situational drama and thriller, by placing it in a concentration camp set up by these machines, where survivors are making attempts to escape. It is the background of this fictional world that is abundant with potenmtial new ideas and allegories.

I'd bring back the iconic scenes/sets from the first Terminator movie. The Tech Noir club is a must, The Alamo Sports and Gun Shop, and Big Jeff's restaurant. Also, use the original motorcycle model, the original Terminator sunglasses, the Plasma Cannon rifle used by the infiltrator terminator, feature a 12 gauge autoloader, 45 long slide w/laser sighting, AR-18 Carbine, SPAS-12 shotgun, UZI 9MM, for fun include phased plasma watt rifle in 40 watt range.
Also, since the Terminator story has been told so many times and in so many often terrible ways there's very little you can do to scare the audience. Like "oooh, the world is going to end" so there can't be any forboding scenes, it just won't work, totally a waste of time. I think the audience will appreciate high quality action scenes with a big helping of the original sets, because that's what they're looking for: Nostalgia.

The Terminator accidently goes to the wrong place and time and, through confusion, kills the wrong people. Innocent people get murdered. Make it low budget, maybe indie like the original film. Gory, dark, and violent horror film about an unstoppable machine.