I've always wondered how unification between Vulcan and Romulus would work, especially considering that Vulcan and Romulus are so distant and Vulcan is part of the Federation.
Distant philosophically, perhaps - but there's little evidence that Romulus would be far away from Vulcan in terms of lightyears.
In the original Unification episodes, the trip from Romulus to Vulcan in a fleet of old tubs actually takes very little time. For all we know, it's a shorter hop from Vulcan to the Romulan Neutral Zone than it is from Earth to Vulcan, and Romulus might lurk right behind the Zone.
Granted that the Romulans probably would want to put distance between themselves and the planet they abandoned in disgust or fear. But perhaps they weren't able to travel far. Or perhaps they never really "left", and the relatively proximal Vulcan colony named Romulus simply stopped answering Vulcan vidiphone calls, and started shooting down visiting Vulcan ships?
Would the Romulans join the Federation? Would Vulcan split from the Federation and join the Romulan Empire (unlikely)?
I rather think the latter is the more likely scenario. What do the Vulcans need the Federation for? It was convenient back when there was this big war with Romulus. But the Vulcans have been dealing with, say, Klingons just fine all on their own, as per "The Vulcan Hello".
So perhaps Romulans agree to worship Surak, and Vulcan agrees to join the New Star Empire? But Vulcans might also give up their silly attempt at suppressing emotion, and the Romulans would join... What exactly? They'd probably see little value in the Federation being run by Admiral Vance. If Burnham is to sell them futures, she better give the speech of her life.
Timo Saloniemi