Right off the bat, we have a scene where Spock is born. The thrust of the scene is Spock’s mother Amanda expressing her displeasure with Sarek when he isn’t present for the birth and then doesn’t understand the emotional implications of this. One gets the feeling that this probably happened an awful lot in this relationship. The script then jumps to the scene where Kirk is born, which is where the movie opened.
There’s a lot more SPOILERIFIC stuff you can check out by clicking HERE. It gives you good insight into how filmmakers craft a finished product, what they think can work, what they think can’t work and what could have worked but they still decided to cut.