Valeris in Star Trek VI was supposed to be Saavik, but they decided against it at the last minute.
That would have been a more shocking betrayal.
P.S. If you ever wanted to see Valeris taking a hot shower, the 1992 Rutger Hauer action flick Split Second is for you. Kim Cattrall made it right after VI, and still sports her Vulcan haircut. 😉