If VI had featured Saavik instead of Valeris as the traitor

[Timo]

No they didn't. Chekov was an only child.

Says Sulu, and Sulu only. Why should we trust his word over the word of the man himself?

Timo Saloniemi

 

[Melakon]

Either Kirk or McCoy should have been familiar enough with details of Chekov's family relationships to know whether there was a brother, rather than taking Sulu's word for it. Both of them must have reviewed his personal and/or medical files. Accepting Sulu's word as authority seems questionable, as this is the guy who thought himself one of the Three Musketeers, and went loopy over Landru.

 

[Allyn Gibson]

Of course I don't know why they had to out-continuity her in TVH, since she's been shown in the comic series' as being a great character. In DC's run she practically became part of the crew's family!

Perhaps Nimoy and/or Bennett didn't enjoy the experience of working with her and/or her performance in Star Trek III. They couldn't not bring her back in Star Trek IV given where the film starts and where we last saw the crew, but that also doesn't mean they had to give her a meaningful role. In that case, they gave her the bare minimum to explain where she's gone, and that's that.

The other possibility. Nick Meyer wrote the San Francisco half of the script. He didn't want to work with Curtis years later on Star Trek VI; perhaps that went back years earlier and he had no interest in writing for Curtis' Saavik on Star Trek IV. If that's so, then Meyer's half of the script didn't use her, so Bennett had to write Saavik out to explain why she's not there in the middle half of the film.

Or, they simply couldn't come up with anything for the character to do in Star Trek IV, so it was easier to write the character out for the film than have the character hang around like a useless fifth wheel.

 

[Therin of Andor]

Hence The Pandora Principle giving Saavik a backstory where she was sole survivor of a failed colony, and wasn't rescued until she was almost ten. Her control is dodgy in STII because it's not something she was taught from birth.

The backstory is from the ST II and ST III novelizations. "The Pandora Principle" simply expanded on Vonda McIntyre's work.

Or, they simply couldn't come up with anything for the character to do in Star Trek IV, so it was easier to write the character out for the film than have the character hang around like a useless fifth wheel.

In a "Starlog" interview, Bennett once said that Saavik in San Francisco was yet another Vulcan who'd have to cover her ears to go out in public. It kinda thinned out the joke. The other option was to leave her looking after the Bounty, and she was still contributing nothing.