1. Nobody thinking of putting on the helmet to finish McCoy's work after the knowledge wore off
2. Having Spock assist in his own surgery should have been scrubbed.
I could have sworn it was said that to put the helmet back on McCoy would have killed him? Or I'm imagining it.
Spock talking McCoy through the surgery was just a new level of stupid. It would have been worse if the actors camped it up but they played it with sincerity, which would be extremely difficult to do.
1) Depict the women as having average intelligence, and possessing knowledge consistent with living in a technological society. The "teacher" would give more still.
2) Have only part of Spock's brain taken, this would explain how he was still alive and later able to move around with the assistance of the device on the outside of his head. When putting Spock's brain back in McCoy was working on the top of Spock's head and not the where the brain joins the spine.
The episode was trying to do the ye olde "battle o' t' sexes" gimmick, but also being late-1960s was also misogynist thanks to needing the magic machine. Thankfully the (cave)men were presented as being pretty much dumb too.
While gross, that idea of only a big chunk of his brain having been taken almost works.
Still, the episode - on top of everything else - also both compounds
and upends the "computers are evil" shtick because now we have a human running the computers, albeit a brain lumped into a big box with Sargon's globe on top and with plastic beams and three buttons poorly spaced on the pedestal below because fog and lasers weren't cost efficient yet and how nobody cared about season 3's props looking as if anyone cared.
But for basic HVAC functionality, any old Sinclair ZX81 would suffice. Plopping Spock's noodle out of his noggin is just extravagance beyond tacky. Just like phraseology such as "noodle out of his noggin" is.
Then again, it's still the same TOS theme of "computer running the joint and all the humans waddling around are too dumb." And since Spock is involved, Kirk wasn't going to nag the computer into blowing up.
Never mind all sorts of questions on how the complex is powered, or when the blobby brain inside the globe dies how come the system is still operational until the go-go-gadget dancers find a new brain to plop in? No backup systems? No because episode dialogue overtly states that without Spock's brain the system will fail and they will have to go out of their caves and get busy with the cavemen again.