One thing that always annoys me about Trek generally - even in the Abrams universe - is they always have fantastic engineering solutions to problems that later get lost and forgotten about and are simply used as plot devices. So, in the Abrams universe - why wasn't Spock's far advanced ship reverse engineered with technology from presumably over 100 years in the future? With that technology Star Fleet could defeat any enemy - I guess with the exception of the Q or other omnipotent beings.
Ah shit, I forgot. Thanks. Nonetheless, the older version of Spock sure could give the federation that exists now a big head start from everyone else in the Alpha Quadrant.
I'm sure there's some Alternate Universe Prime Directive or some other nonsense that would be broken by any such interference.
Realistically, if Spock Prime's existence in this timeline became known, he'd probably have half the galaxy after him for his technical knowledge if nothing else. Even if Starfleet were noble enough not to use him for their own purposes, they'd have no choice but to hide him away somewhere, willingly or not, just to prevent anyone else from getting him. My guess is that Spock Prime has not revealed his true identity to anyone but Kirk and his younger self, and that he would strive to minimize interfering in the timeline except where necessary to correct previous interference, which was basically his modus operandi in the last movie.
Spock Prime said he wasn't going to hide himself at the end of the movie. He's out enough to have been the guy who chose the planet for the new Vulcan colony, and by the way he was watching Kirk's appointment as captain, I wouldn't be suprised if he had a hand in that too. However, Scotty says in Star Trek Ongoing #15 that he's refusing to share details of his future or technology.
Like I said, realistically he probably couldn't get away with that. What he's carrying around in his head would be too valuable, and too many powers throughout the galaxy who don't give a damn about meddling with the timeline, etc.
Well, powers vying for Spock's future knowledge was going to be the subject of the novel The Hazard of Concealing, until Bad Robot had it cancelled. Maybe they'll elaborate more on his status in the next movie - Nimoy was rumoured to be in it (in "long and stately robes") after all.
I'm guessing he told his younger counterpart: "If you ever run across an old DY-100 class ship, blast it out of the stars."