Therin of Andor wrote:
Do you want him to save Amanda, too? Kirk's father? Chief Engineer Olsen? Cadets who get killed in the movie? Where is the cut-off? All the characters probably have dead relatives they'd like him to return.
In the DS9 episode Trials and Tribblations
Sisko et al were able to successfully restore the original timeline without causing a lot of harm.
Spock could have gone back to the original incursion by Nero and fixed it there.