I did a quick check, and "Assignment Earth" and TVH were the only TOS stories where Kirk and crew deliberately attempted time travel in their starship. They traveled from the past back to their time in "Tomorrow is Yesterday", but they were thrown into the past by accident. In "City", they used the Guardian. That's also the only TOS reset episode I'm aware of off the top of my head. There were only two other episodes with time travel: "The Nake Time" (just three days) and "All Our Yesterdays". "City" was the only real reset.
Even in TNG, there were only about ten time travel episodes over seven seasons, plus FC, and I think only a couple of those were "reset" type episodes.
VOY was the series that kept pushing the reset button. Find Janeway in the new universe, she'll have no problem going back to save Vulcan.
I guess where things got sidetracked is in discussing whether Spock Prime, or even Spock should attempt to go back and save Vulcan. Rereading teacake's OP, teacake is speaking about some Vulcan or Vulcans obsessing with the idea of going back in time to save the planet. That is a separate issue, and I've said I think that in Trek there's time travel of the type the Spock and Nero experience, and time travel within a timeline. I guess my point would be that any Vulcans who wanted to attempt this they could, but within temporal ethics, it would be wrong because they are not trying to prevent an event that was not supposed to happen. They are not "healing" a timeline, they are destroying one because they prefer the other. A subtle but important difference that should make us all glad this can't happen in reality.