Surely the Vulcan society depicted in Trek didn't spring into existence overnight. Surak promoted logic over emotion for Vulcans, but was emotional suppression the original goal, or was it a trait that developed post-Surak? Using logic and embracing inner peace don't require emotional suppression, but that may have happened over the centuries as Surak's followers grew and his philosophy took hold among the population.
Is the choice for every Vulcan really either "raging violent berserker" or "unemotional robot"? Clearly some 22nd and 23rd century Vulcans could be emotional but not exceptionally violent. I wonder if part of the problem for Vulcan society was the existence of telepaths. Sarek was able to unconsciously project some of his emotions onto other people when he was ill with Bendii syndrome. If, in the Vulcan past, some raging berserker telepaths existed, might they have projected violent emotions onto others, spreading conflict?
according to "the savage curtain," Surak believed in emotional suppression. But as you say, embracing peace and logic don't require emotional suppression, so I'm not quite sure why they got lumped together. The telepathy idea is a good one, but again, Sybok kind of contradicts that.