That's an interesting idea: a member of Nero's crew becoming basicly the anti Spock Prime with only one goal in mind: Protect the Empire! (from it's enemies, itself, and the supernova) If you wanted TCW involvement, perhaps he is a temporal agent, or maybe he was saved at the last second by one (that would limit time travel; he's on his own, perhaps with something to prove his story to current era Romulans). He now acts as an advisor to the Praetor, leading the Star Empire to both un-imagined new technologies and undreamed of glory and conquests, forcing Spock prime to take a similar role to prevent Romulan supremacy.
But what is the end goal, if there IS TCW stuff afoot? Perhaps a more miltaristic Starfleet, secretly lead to new levels of tech and discovery by Spock Prime, goes to war with a greatly empowered Star Empire, eventually leading to the fall of both governments and the rise of a new power (klingons? Borg? Dominon? some new or forgotten race, like the Husnock?)
Interesting thought, concerning the never seen Husnock: Thanks to Time travel, the effect can sometimes create it's own cause. With the changes in the Timeline, they weren't wiped out by an angry Douwd. In their future, they realize what happened to them (somehow) and decide to change the timline to fit their needs, leading them to attempt to start a second Romulan War!
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"Yes, it's the Apocalypse alright. I always thought I'd have a hand in it"
Professor Farnsworth