Force Awakens worked because there hadn't been a Star Wars movie in a decade and the film promised to be closer to the ST than to the PT. Any damage done by the PT was allowed to heal through time, the old cast was set to return, and it being taken over by Disney gave fans hope of something fresh and exciting.
Say what you will about it, but it worked in the short term for one movie.
Oh and Force Awakens also had a fair amount of mystery surrounding the plot...whereas Terminator DF did the exact same fucking plot I've already seen in multiple Terminator movies. Time Traveling Killer Robot + Messiah for the Future + Protector for Future Jesus = Terminator plot. Wash...rinse...repeat...shoot me in the fucking head.
Terminator is a franchise that has been buttfucked since the turn of the century. In the last 16 years before this film, we had 3 attempts at a Terminator sequel, including a crazy as fuck movie that basically undid the first two movies...the ones that people liked. We had already seen Arnold come back, so him as the Terminator has lost its nostalgic value, and I doubt anybody had any faith that there would ever be a good Terminator movie again. The timeline of these films is a confused mess and the films haven't been good for a long time.
When I heard that Dark Fate was coming out, before I knew anything about Cameron, Arnold, and Hamilton all coming back, my first reaction was "Oh no". I think most people reacted that same way, and it just didn't matter what they put in the movie or who they cast...another Terminator sequel so soon after all the other disasters like Genesys.