Spock's Brain is a mixture of awkward ideas and moments, and bits that actually work, despite everything.
Positives:
1) The scene is Sickbay is sold very well with the acting. Adequate weight is given to what happened.
2) The conference on the Bridge is interesting... and Uhura has a good moment, asking what the hell the point of taking the brain would be.
3) I like the strange, cold, bleak, hopeless feel to this story. For once, they're not representatives of the powerful Federation, able to let a starship's weaponry speak for them. They've been reduced to a semi-desperate handful of people out of their depth, in a bizarre, probably hopeless search to save their friend.
4) Unlike every other viewer apparently, I have always found the first sight of Spock's body standing there with no brain in that skull to be effectively horrific.
5) The SF idea of a brain doing the work of maintaining a society's tech rather than a body is a good one.
6) We get one of the best McCoy scenes ever, where he's transformed by this unimaginable knowledge from the Teacher. It's a shame that when a questionable premise is sold so well by actors, with total commitment, that so few fans seem to notice or appreciate it. McCoy's desperation is well played... anyone with an imagination and empathy ought to be affected by the performance. Rob't Justman's idea of having Spock chime in on how to finish the operation was clever...
Really, the bad bits are so glaring (for me, mostly the Space Bimbos, their acting, their costumes) that it's more interesting to look for the good amongst all this, than fixate on the obvious flaws.
And I continue to be frustrated by people missing the point of the "entertainment" in Plato's Stepchildren. Of course it makes you cringe to watch this. That's the point. Kirk and Spock are being degraded and humiliated. Maybe we just don't value dignity anymore, so we don't empathize when we see it taken away.
