How about this idea...

Full reboot. None of the previous films has any bearing on the new film.

Plot - the heroes go FORWARD in time to destroy Skynet. They battle Terminators and Skynet. Can they stop Skynet and save their past or will the Terminators preserve the future timeline?

It's a full 180 degrees plot! All the previous Terminator films were about going back in time (except Salvation) but in the full reboot the main characters go forward in time to save the past. A twist could be Skynet never invented time travel. It was invented in the 1980s and when the heroes go forward in time to the 21st century Skynet captures one of the heroes and they reveal how time travel works. The paradox is time travel doesn't exist in the future, merely in the past. Only a select few in the 1980s knew of the technology.

Terminator 1984 was about Kyle Reese going back in time to save the future. But what if the opposite happened. The main character (or characters) go forward in time to save the past?