I hope the novels don't go anywhere with this. Not all Vulcans have the same ability to control their emotions. Some, like Captain Solok from DS9, are clearly ignorant racist jackasses who have very *little* emotional control (don't even try to tell me Solok was acting logically). Others, such as Spock and Sarek, are very good at it.
As for T'Pol, her trellium-D addiction damaged her own sense of control. I know they said that in ENT at least once. So there is no need for Romulan involvement...