My spoiler-laden thoughts about Terminator Salvation and Terminator in genreral
Okay, first a disclaimer: This post contains major spoilers about all 4 Terminator movies, so if you haven't seen them yet but still want to, you may want to leave now.
Before talking about Terminator 4, I'd like to spend some time talking about T3 and T2. When asked about Terminator 3, James Cameron said that he had finished his story with Terminator 2. This also seems to be the majority of fan opinions: T2 was a stellar sequel to a good movie, concluding the story. Two Terminator movies, Cyberdyne destroyed, Sarah and John Connor alive, all is good. But the Terminator universe had more potential. I remember playing Bethesda's First Person Shooter games - Terminator: Future Shock and Terminator: SkyNET - in the mid-90's, and I was fascinated by the dark atmosphere and the way the game builds suspense by the simple fact that not much happens at times, but you still have to expect a sudden robot attack at all time. While those games are non-canon, they prove that the man-machine war has a lot of potential for good storytelling. I always look at the Star Wars franchise, where the Expanded Universe - stories by authors other than Lucasfilm - has brought us some great characters and stories, sometimes on par with the original movies. So just like George Lucas' Star Wars universe was brought in many new directions, so could the Terminator universe be. The potential is certainly there.
I do not know the exact reason why T3 was made, but from watching the movie, I see a sole purpose: Make sure that T2 was not the end and lay the groundwork on which future films can built. Yes, T3 was not as good as it could have been. Yes, to some people it feels like an irrelevant movie. But with the purpose in mind, T3 could never have been a movie on par with T1 or T2, because there was just no chance to really add something new. The movies job is to save John Connor and start Judgement Day, and the movie does that job. Terminator 2 had an ending, Terminator 3 had a new beginning.
So while T3 had an excuse to just be an "Okay" movie, Terminator Salvation (T4) has no excuses whatsoever. Quite the opposite, it's just rightful to expect T4 to be near T1 in terms of quality, because it is a) mostly free of any story constraints and b) starting a new series. When doing T4, the creators had the choice which characters to focus on and which part of the story to tell, and actually they made a decision that I support: They did not create it as a prequel to T1. This is not really the story of John Connor, this is not about sending Kyle Reese back into time. They went to a point before that, and this is a decision that I applaud. Sadly, it's one of the only things I really applaud about the movie, but more on that later.
So at the beginning of the movie we learn that SkyNET is about to produce it's new Terminator, the T-800. We learn that John Connor is not the leader of the resistance, because some see him as false prophet. We also learn about a guy called Marcus Wright who is executed in 2003, but allowed Cyberdyne to use his body afterwards. This is where the first of many ridiculous events happen, as Marcus agrees on the condition that he gets a kiss by the doctor. That really looked stupid and forced, mainly because we do not know the doctor at this point. Later when Marcus is in the SkyNET HQ, we see an illusion of the doctor giving a speech, and here I see a lot of wasted potential because the character is just not developed at all. I hope that T5 adds just a bit more life to her character, otherwise this is just wasted.
Seeing Marcus reincarnated after the discovery of the T-800 of course already makes everyone in the audience believe that Marcus is a Terminator. I liked this part mostly, because the idea of an Infiltrator who does not even know about it is good, although of course not very original (Sleeper Agents and such). I just had the feeling that they tried a bit too hard to re-create the Terminator 2 effect where everyone was believing that Robert Patrick is the good guy and Arnold the bad guy. But Marcus acts too much like a machine to really have the audience feel with him. Also, the second really ridiculous scene happens around Marcus again, this time it's that love plot with Blair Williams. I mean: They barely met, he is beating up some guys who tried to assault her and she is instantly falling in love. Seriously, it's not like there are not enough men left in this world to take the time to pick one, right? That felt really stupid.
Ridiculous Scene number 3 is everything involving the transporters. Seriously, seeing that huge Machine taking prisoners is one thing, but then it stands up and launches two Mototerminators from it's legs? WHAT THE F***? I actually had to double check that I'm not accidentially sitting in Transformers 2 instead of Terminator 4, because this felt so out of place, like another forced homage to T2, this time the motorcycle chase. Oh, and don't get me started on the USB-Ports that those Mototerminators have...
Speaking of forced homages: So Kyle Reese delivers his "Come with me if you want to live" line, and John Connor gets a chance to say "I'll be back", but both occurrences are out of place and badly timed. In John Connors case, it was just completely obsolete, and I don't see any chance for him to deliver that line anywhere in the movie without it being stupid. On the other hand, Kyle had more potential. In the movie, he is still very young and inexperienced, so they could have given him the "Come with me..." line as some sort of signature line, but as he is so young, it could have been like a pickup line that needs perfection. That could have worked if they a) used it a bit more often and progressively improved it or b) used it on characters that are properly developed. Instead, he uses it on Marcus at a point where we know neither Marcus not Kyle. I would have placed it just a little bit further, maybe after the Hunter-Killer destroys the building. That would be a good place to have a little talk and then Kyle could offer Marcus to come with him if he wants to live.
One homage that I really liked what the fight between John, Marcus and the skeleton T-800, because that was mirroring the T1 climax (with some T2 elements thrown in) very well, but it was placed in the proper place in the movie and properly integrated. This is really a homage that worked. Also, the T-800 that looked like Arnold from T1 was great, although his introduction (smashing the door of a holding cell) was unnecessary weak.
And then, there is the ending. I have seen many bad endings, illogical endings, ridiculous endings, out of place endings, downright stupid endings. But this here takes the cake. So John Connor is stabbed by the T-800 and barely rescued, lying on the table, more or less dying because his heart will not make it. And then Marcus offers to take his heart. Seriously, not even a double facepalm is strong enough for this. I was expecting two different outcomes after John was stabbed: a) He dies, and then Marcus takes over. That would be kind of a plot hole but could still be stretched a bit to fit. In his dying words, John could have given Kyle the photo of Sarah and tell him to go to the past once the time comes. Kyle could then have decided not to tell Sarah about the death of her future son, which could also be used to resolve the resulting anachronism. Overall, the death of John Connor would be one solution, but maybe not the best one. Then there is b) John is killed without anyone noticing, and then replaced my a Terminator, similar to Marcus. Maybe even Marcus could turn out to be evil and involved in the death of John. That would have some serious potential for the future.
But killing off Marcus to give a heart transplantation? I mean, let's forget about things like organ-incompatibilities and the fact that sterile operating rooms are unlikely to exist. No, the ending is such a big fail because it highlights the fact that both Marcus and John are seriously underdeveloped and the audience is unlikely to care about even one of them, certainly not both.
So while T4 added some interesting story bits, and while the scenes in SkyNET were quite good, it is ultimately a disappointment because of all the wasted potential. Underdeveloped characters, badly timed and executed homages, a forced love plot and action scenes that would fit a Transformers or Matrix movie really bring down the movie. I mean, it's one thing if your movie does not have a lot of potential from the beginning (Like T3), but it's another thing to really mess up if there is so much room for excellency. There is sadly not a single character in the entire movie who really goes through some character development, which is possibly it's biggest fault. At the beginning I was saying that I like the decision not to have John Connor as the focus point, but to look at other characters. Unfortunately the character they picked as the main character - Marcus - is killed off at the end without leaving anything behind, which means he is just a throwaway-character. They should have focused on Kyle Reese in my opinion, because he should be the main character of Terminator 5 and could have used some more focus to turn from a naive and inexperienced boy into the man he is in Terminator 1.
Conclusion: Terminator 4 is just irrelevant, because it adds absolutely nothing new to the universe. The movie has simply no purpose, no goal, no mission, no lasting value - which puts it at the opposite of Terminator 3 which at least had a clear goal and executed it.