Ok well my opinion is the only thing bad about the movie is the previous 2 movies before it because they are holding it back from making the sells it should be making. James Cameron has already put his stamp of approval on this movie saying that it should've been the 3rd installment.
It Genisys Skynet got tired of losing to John Connor no matter how many times they tried to stop John Connor with Time travel somehow he still manages to do it and stop Skynet. They create a new Terminator that can turn people into Terminators replacing them at a cellular level. John Connor isn't a bad guy because he wants to be its because Skynet forced him to become a Terminator and thats what Trailer 2 shows us. They also jump the timeline from 1984 to 2017 rearing it for a sequel that they probably hope to put out then.
Also if you make your judgement of seeing movies based off reviews then I don't know why you see movies in the first place. Reviews are opinions of people and some people use their bias opinions to sway people. You don't know how good a movie is until you actually sit down and see it.
Now to the topic at hand, the Starchild isn't really a legitimate connection. That was just the program at its early stages as it got closer to going out to the world you see as it matures and changes forms.
On sidenote The Doctor decided to doom humanity, in this version of the Doctor he hates humanity and whats to see it perish 