One thing that still puzzles me is Q's offhand reference in VGR's "Death Wish" to "a misunderstanding which ignited the hundred-year war between the Romulans and the Vulcans." What hundred-year war? Where in all of Trek history is there room for such a war? Nobody on screen or in print has ever picked up on this or explained it. Maybe by "Romulans," Q meant the forebears of the Romulans, the faction that departed in the Sundering. Maybe they fought for a hundred years before deciding to leave Vulcan. Not sure that meshes with the books, though.
Sorry, I guess I'm missing something here, but aren't there roughly 17 centuries between The Sundering and Enterprise(and even more between The Sundering & TOS as it would have been at the time of Death Wish) - is that all accounted for already?
Also, I'm not with my books right now, but wasn't there a scene in Spock's World between T'pau & Sarek where they're discussing Sarek going to Earth for the first time, and T'pau tells him not to underestimate them given that they beat the romulans back in x number of years when it took us y number of years - maybe it arose from that?