I think that a lot of interesting and good points have been made here, it's an intriguing question...my first gut reaction was, reading it, to say i'd guess he wouldn't say much, if anything. Who knows for sure? I am sure there'll be those who'll disagree, but it seems that maybe one thing Prime Spock woulkd be inclined to want to do, is to make sure that the Romulan government is at some point made aware of what fate might well befall the Homeworld here, in this new reality he's found himself in-which came about because of actions he took...After all, the destruction of Romulus in the Prime Universe caused Vulcan to be lost here...and Spock will NEVER forget that fact, though move on he must, and will. To me that's a powerful motivating factor to want to see a far better outcome for both the Empire, and those around it.Would this happen soon...of course not. Merely getting the Empire to believe any representative of the Federation would be a major achievement, given the animus since before the Romulan War...but it's possible.In time, and with much work on behalf of someone like Spock, who, at his age, yes, does not have the time he spent in years past to establish a rappor with Romulans...but Young Spock does.And, once Quinto's version has moved forward from his grief and anger-generated by ONE Romulan, not the entire race, dangerous though they may yet be, and we know in time he will, armed also with the knowledge of what might well occur again, he could carry the torch, and become, still, POTENTIALLY, the Ambassador to his people's cousins that his other, future self was, and effect changes in their relationship, i.e., the UFP...and IF the physics follow here, save billions on Romulus, and who knows, create a future unseen yet, even than in the PU. That is part of the point of this new universe, that things are different, and that events may play out on another level. Could it be in some future era a different chaos than the Hobus Disaster?Yes. But it doesn't necessarily have to be either.