Except the Vulcans wouldn't care, if you want to strike fear and terror like that you would need to attack Earth.To strike fear and terror into the Federation? Knowing that the Klingons could even strike at one of the beating hearts of the Federation (Vulcan)?
From Undiscovered Country.Really? I don't remember that being established this early on. They didn't pick up the Klingon ship on the way to, say, K7.
CARTWRIGHT: Negotiations for what?
SPOCK: The dismantling of our space stations and starbases along the Neutral Zone, an end to almost seventy years of unremitting hostility with the Klingons, which the Klingons can no longer afford.
From the Trouble with Tribbles.
UHURA [OC]: Sensors are picking up a Klingon battle cruiser rapidly closing on the station.