Terminator: Salvation, and TSCC, despite their flaws, understood that you can't just keep having machines disguised as humans hunting Sarah or John Connor. That gets stale really fast. Rebooting the franchise to retell that original story and make it "sexier" might do all right in terms of box office, but it is creatively a dead end.
The Terminator story I want is the one that picks up after Rise of the Machines where John Connor emerges from his bunker to form the resistance and the Future War begins. Salvation sort of did this, but was poorly executed and just didn't feel "right" somehow.