My unpopular Terminator opinion is that I think that the first film in the franchise was the only good film of the franchise.
For a low budget film, it sure felt intense, even when the special effects were laughable. It felt almost like I was watching a horror/slasher film. It's my favorite of the series.
Plus, I believe that the sequels undermined the original point of the first Terminator film. It's clear that the first film was scripted with a causal loop in mind for the way time travel worked. In other words, time is set, and cant be changed. John Conner doesn't exist unless Kyle Reese goes back in time, and if I'm not mistaken, the place where the T-101 is defeated at the very end is actually Cyberdyne, meaning that Skynet was built out of the remains of the destroyed T-101, which can't happen unless there was a T-101 there to begin with. I think there are even deleted scenes leading up to the final battle where Kyle and Sarah head toward Cyberdyne to blow it up, to prevent the war from happening, which explains why they ended up at Cyberdyne in the end in the first place, and also makes the film have much more meaning. Skynet thought he could change his fate by preventing the birth of John Conner, while Sarah and Kyle thought they could prevent the war from happening, and the irony is that their attempts were misguided, as anything they do is already meant to happen. It's a pretty deep movie with lots of layers, when you think about it. The first time I saw the movie, it gave me a lot to think about.
Then, the sequel comes along and renders the whole point moot. While John is still said to be Kyle's son, and Cyberdyne still apparently is building Skynet from the remains of the T-101, the future is actually changeable in the sequel. I could go with the fan theory that John Conner was originally a different person with a different father, and the events of the first film erased him from existence and brought a different John Conner into the world, but I honestly don't buy it. It's clear watching the first film that the original intention of the filmmakers was to portray time travel as working in a causal loop. And let's not even mention the ending of the second film. It makes no sense. John basically erases Skynet from existence, but wouldnt that also mean that Kyle never traveled back in time to bring him into existence? I was scratching my head at the end of the second film. Of course, the third film retcons the events from the end of the second film, but by then, the concept was getting old.
No, the first film is the best, and in my opinion, is the only one that makes any dang sense.