I have the opposite opinion. The dramatic beat would have been so much better if she was Saavik turned traitor to avenge the loss of David. The audience has no connection to Valeris and therefore her turn has no impact.
Imagine the impact if Spock broke contact not because "she does not know" but because Saavik showed him their son, conceived on Genesis, and born in secret on Vulcan, known only to Amanda? Why else would Saavik stay on Vulcan with Amanda, as shown at the beginning of ST4?
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