Okay...so if Nero goes to an alternate timeline to try and kill Kirk or whatever...then why does spock follow him??? If nothing he does will change history, at least not Spock's timeline's history, then why not let the lunatic vanish forever and be done with it all?
And before you say that Spock is still trying to protect people, his friends, just alternate versions of them that will be harmed by Nero...there are infinite alternate timelines and in many Kirk and Co. are likely getting killed by the second.
This all seems ridiculous and unneeded. Timelines. For god's sake.