Therin of Andor wrote:
Of course we do.
I don't know who was responsible, and, honestly, I doubt we will ever conclusively know.
Roddenberry was quoted as not liking the idea of a traitorous Saavik because she was supposedly "a beloved character" - but then, Roddenberry came to dislike the idea of any latter day Starfleet characters turning traitorous - and Meyer laughs about this objection in the ST VI commentary because he says that Roddenberry originally opposed the introduction of Saavik in ST II; Saavik was a creation of Meyer's and he reckoned he had a right to turn her into a traitor. She was originally "Dr Savik", a young male
Vulcan in a very different ST II movie premise, and fills a similar role to Roddenberry's Xon ("Phase II") and Livingston's Sonak (TMP).
Roddenberry must've forgotten that he wrote "The Omega Glory", in which a corrupted Starfleet captain is a major character.
But, as pointed out, above, Gene had fairly little to do with the movies after TMP.