Bottom line: I think this episode is awesome, possibly among my top-ten best TOS episodes. Criticizing it for "sexism" has always seemed short-sighted to me.
Even aside from the sexism, it's still a pretty bad episode. It does have its moments; there's some good potential in the story of an impostor taking over as Kirk and the real Kirk being helpless and unbelieved, and there's effective tension as the crew's suspicions build up and they slowly turn against the impostor. The scene between Scotty and McCoy in the corridor, discussing their vote and the prospect of mutiny, is one of the best scenes Doohan and Kelley had in the entire series, with terrific performances from both.
But it has serious storytelling flaws, degenerating into silliness in the final act. Logic is thrown out the window. At first, the military terminology is quite accurate, with Janice-as-Kirk calling for a preliminary hearing to decide whether a court-martial needed to be convened, and if so, on what charges and specifications. But right after the Scott-McCoy corridor scene, Janice-Kirk just leapfrogs over the actual trial and calls for summary execution. And while there are protests raised against that, nobody points out the gross violation of procedure. Not to mention that the corny instant replay of the corridor conversation totally undermines what had been a powerful scene up to that point. Not to mention that it's a lazy cheat when the antagonist self-destructs and makes things easy for the heroes. Not to mention that the heroes didn't even do
anything to resolve the situation; the transference just reversed on its own at a convenient moment, a huge storytelling cheat.
Come to think of it, when they were going on about evidence, why didn't Spock propose returning to Camus II to study the equipment? That would've been the most logical way to reverse the transfer -- simply by going back to the machine and repeating the process. It was sloppy that the machine just got forgotten.
It was also a deeply disappointing entry in the genre of body-switch stories, because the fun of such stories is seeing actors mimic each other's characters, but Shatner and Smith made zero attempt to mimic each other. Shatner is just playing his idea of a generic female and Smith is playing her idea of a generic male. Which basically means he's campy and petulant while she's harsh and grating. Granted, it's hard to get that kind of mutual imitation right when it's with a guest star just coming in for a week, instead of someone you've worked alongside for some time and gotten to know. Still, one wishes director Herb Wallerstein had put a little more effort into this -- at least had the actors record each other's lines and let them review the tapes overnight or something.