Originally Posted by
MisterPL
The Undiscovered Country could have been a great mystery flick had it not been for one fatal flaw.
Since director Nicholas Meyer couldn't get Kirstie Alley back as Saavik, instead of using Robin Curtis (who'd played the role twice), he chose to cast Kim Cattrall as Valeris. His reasoning was that he created Saavik and if he couldn't get Alley then he'd create another character.
The story would have had much more punch if Spock's already-established (and trusted) protege had been the traitor.